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Compiling ACPI v2.0 driver for Windows XP SP3 and Windows 2003 SP2 (x32/x64)


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Posted (edited)

Hi,

I am going to build from scratch a Lan driver for XP SP3 for any i219.

I use Ndis5.1 original from XP, not Ndis6 from Vista, win7 etc.

Just now, for the very first time, I get this my lan driver startet under XP.

Oh crazy..what a hard work with Windbg

Dietmar

cooli219.jpg

 

0: kd> !devnode 8b5e8ee8
DevNode 0x8b5e8ee8 for PDO 0x8b51ccf8
  Parent 0x8b5e9998   Sibling 0x8b5e8dc8   Child 0000000000   
  InstancePath is "PCI\VEN_8086&DEV_15B8&SUBSYS_15B81849&REV_00\3&11583659&0&FE"
  ServiceName is "i219"
  State = DeviceNodeStarted (0x308)
  Previous State = DeviceNodeEnumerateCompletion (0x30d)
  StateHistory[07] = DeviceNodeEnumerateCompletion (0x30d)
  StateHistory[06] = DeviceNodeStarted (0x308)
  StateHistory[05] = DeviceNodeStartPostWork (0x307)
  StateHistory[04] = DeviceNodeStartCompletion (0x306)
  StateHistory[03] = DeviceNodeResourcesAssigned (0x304)
  StateHistory[02] = DeviceNodeDriversAdded (0x303)
  StateHistory[01] = DeviceNodeInitialized (0x302)
  StateHistory[00] = DeviceNodeUninitialized (0x301)
  StateHistory[19] = Unknown State (0x0)
  StateHistory[18] = Unknown State (0x0)
  StateHistory[17] = Unknown State (0x0)
  StateHistory[16] = Unknown State (0x0)
  StateHistory[15] = Unknown State (0x0)
  StateHistory[14] = Unknown State (0x0)
  StateHistory[13] = Unknown State (0x0)
  StateHistory[12] = Unknown State (0x0)
  StateHistory[11] = Unknown State (0x0)
  StateHistory[10] = Unknown State (0x0)
  StateHistory[09] = Unknown State (0x0)
  StateHistory[08] = Unknown State (0x0)
  Flags (0x000000f0)  DNF_ENUMERATED, DNF_IDS_QUERIED, 
                      DNF_HAS_BOOT_CONFIG, DNF_BOOT_CONFIG_RESERVED
  CapabilityFlags (0x00002000)  WakeFromD3

 

Edited by Dietmar

Posted

Hi,

I take all data from Linux for i219 for the registers etc.

Crazy work, 16 hours a day.

Now the driver i219.sys for XP SP3 is nearly ready

Dietmar

ip.jpg

Posted

@Dietmar

Do you think you'd be able to make a similar driver for realtek 2.5gb NICs at some point in the future? I don't have any hardware with intel i219 NICs.

Posted

@Damnation

I think, it can be done for any Nic, as long as you have Linux, where you can spy.

But it is soso crazy hard work.

I notice for example, that I always get Bsod D1, which I cannot catch with Windbg,

only when you make an offline check of it.

It happens, when the lan cable is connected at boottime, but parts of the driver have not loaded

to full, so happens this Bsod even everything is "ok".

Now I understand, why on many compis there is always a big time delay, before you get connected via lan

Dietmar

 

Posted (edited)

====================================================
Intel i219 (DEV_15B8) Windows XP SP3 driver from scratch (NDIS 5.1)
====================================================

Hi,

I’m working on a Windows XP SP3 LAN driver for my Intel i219, written from scratch as an NDIS 5.1 miniport (i219.sys).

I am very happy for any hints about the remaining missing pieces (especially i219 “PCH SPT” specifics).

Here is what I already reach, the confirmed hardware facts, register notes, and the current Supported-OID list.

----------------------------------------------------
1) My used lan adapter on Asrock z370 k6 board
----------------------------------------------------
- NIC: Intel i219 (i219-V2)
- PCI Vendor/Device: 8086:15B8
- MMIO: BAR0 mapped at 0xDF400000, length 0x20000 (128 KB)
- IRQ: legacy line 5, vector 97 (XP HAL/IOAPIC mapping)
- MAC (observed / read from RAL/RAH): 70-85-C2-7E-28-B7
- Current driver build (“v45”) installs and STARTS cleanly in Device Manager and answers basic NDIS OID queries without crashing.

----------------------------------------------------
2) Why i219 is tricky vs i218
----------------------------------------------------
- i218 belongs to the older PCH-LPT / LPTLP (Lynx Point, 8-Series) family.
- i219 belongs to the newer PCH-SPT (Sunrise Point) and later PCH families.

Therefore: “patch only DeviceID” (i218 → i219) is not enough.
A working i219 driver must use the correct i219-family MAC/PHY/NVM init logic (different from i218-family).

----------------------------------------------------
3) Hardware inputs I treat as runtime data (must be read)
----------------------------------------------------
From PCI config space:
- Vendor/Device ID (8086 / 15B8)
- Command register (Bus Master + Memory Space enable)
- BAR0 base + decoded size (here: 0x20000)
- Interrupt pin/line (legacy) and optionally MSI capability
- Power management capability (D0/D3)
- Revision ID, subsystem vendor/device ID (for possible quirks)

From MMIO:
- Classic Intel GbE register model (“E1000-ish”)

----------------------------------------------------
4) Minimal register map I’m using (layered bring-up)
----------------------------------------------------
(Full 128 KB MMIO window is huge; I focus on the layers needed for a real driver.)

4.1 Core control / status / PHY/NVM
- CTRL      0x00000  (reset / link control)
- STATUS    0x00008  (link-up bit etc.)
- EECD      0x00010  (EEPROM/flash control)
- EERD      0x00014  (EEPROM read)
- CTRL_EXT  0x00018  (extended control)
- MDIC      0x00020  (MDIO/PHY access)
- FEXTNVM   0x00028  (PCH-family helper register)

i218 vs i219 note:
The register “existence” looks similar, but the correct init sequence and interpretation is family-path dependent (i218=pch_lpt vs i219=pch_spt).

4.2 Interrupts (currently I use polled mode)
- ICR  0x000C0 (cause read/ack)
- IMS  0x000D0 (mask set)
- IMC  0x000D8 (mask clear)
- (ITR is optional)

4.3 RX/TX engine registers
Receive:
- RCTL   0x00100  (RX enable + filters)
- RDBAL  0x02800 / RDBAH 0x02804
- RDLEN  0x02808
- RDH    0x02810 / RDT   0x02818

Transmit:
- TCTL   0x00400  (TX enable)
- TIPG   0x00410
- TDBAL  0x03800 / TDBAH 0x03804
- TDLEN  0x03808
- TDH    0x03810 / TDT   0x03818

4.4 Address filtering tables (important for DHCP/ARP/multicast)
- RAL0/RAH0  0x05400 / 0x05404 (RAR0)
- MTA        0x05200 (multicast hash table)
- VFTA       0x05600 (optional VLAN filter)

Important:
When Windows sets OID_802_3_MULTICAST_LIST, the driver must program MTA accordingly (or choose a safe fallback strategy).

----------------------------------------------------
5) Supported OIDs in v45 (current list)
----------------------------------------------------
static const NDIS_OID g_SupportedOids[] = {
    OID_GEN_SUPPORTED_LIST,
    OID_GEN_HARDWARE_STATUS,
    OID_GEN_MEDIA_SUPPORTED,
    OID_GEN_MEDIA_IN_USE,
    OID_GEN_MEDIA_CONNECT_STATUS,
    OID_GEN_MAXIMUM_FRAME_SIZE,
    OID_GEN_MAXIMUM_TOTAL_SIZE,
    OID_GEN_LINK_SPEED,
    OID_GEN_XMIT_OK,
    OID_GEN_RCV_OK,
    OID_GEN_XMIT_ERROR,
    OID_GEN_RCV_ERROR,
    OID_GEN_RCV_NO_BUFFER,
    OID_GEN_TRANSMIT_BUFFER_SPACE,
    OID_GEN_RECEIVE_BUFFER_SPACE,
    OID_GEN_TRANSMIT_BLOCK_SIZE,
    OID_GEN_RECEIVE_BLOCK_SIZE,
    OID_GEN_VENDOR_ID,
    OID_GEN_VENDOR_DESCRIPTION,
    OID_GEN_DRIVER_VERSION,
    OID_GEN_VENDOR_DRIVER_VERSION,
    OID_GEN_CURRENT_PACKET_FILTER,
    OID_GEN_CURRENT_LOOKAHEAD,
    OID_GEN_PROTOCOL_OPTIONS,
    OID_GEN_MAC_OPTIONS,
    OID_GEN_MAXIMUM_SEND_PACKETS,
    OID_GEN_MAXIMUM_LOOKAHEAD,
    OID_802_3_PERMANENT_ADDRESS,
    OID_802_3_CURRENT_ADDRESS,
    OID_802_3_MAXIMUM_LIST_SIZE,
    OID_802_3_MULTICAST_LIST
};

Numeric OID values (standard ntddndis.h definitions):
- OID_GEN_SUPPORTED_LIST         = 0x00010101
- OID_GEN_HARDWARE_STATUS        = 0x00010102
- OID_GEN_MEDIA_SUPPORTED        = 0x00010103
- OID_GEN_MEDIA_IN_USE           = 0x00010104
- OID_GEN_MAXIMUM_LOOKAHEAD      = 0x00010105
- OID_GEN_MAXIMUM_FRAME_SIZE     = 0x00010106
- OID_GEN_LINK_SPEED             = 0x00010107
- OID_GEN_TRANSMIT_BUFFER_SPACE  = 0x00010108
- OID_GEN_RECEIVE_BUFFER_SPACE   = 0x00010109
- OID_GEN_TRANSMIT_BLOCK_SIZE    = 0x0001010A
- OID_GEN_RECEIVE_BLOCK_SIZE     = 0x0001010B
- OID_GEN_VENDOR_ID              = 0x0001010C
- OID_GEN_VENDOR_DESCRIPTION     = 0x0001010D
- OID_GEN_CURRENT_PACKET_FILTER  = 0x0001010E
- OID_GEN_CURRENT_LOOKAHEAD      = 0x0001010F
- OID_GEN_DRIVER_VERSION         = 0x00010110
- OID_GEN_MAXIMUM_TOTAL_SIZE     = 0x00010111
- OID_GEN_PROTOCOL_OPTIONS       = 0x00010112
- OID_GEN_MAC_OPTIONS            = 0x00010113
- OID_GEN_MEDIA_CONNECT_STATUS   = 0x00010114
- OID_GEN_MAXIMUM_SEND_PACKETS   = 0x00010115
- OID_GEN_VENDOR_DRIVER_VERSION  = 0x00010116
- OID_GEN_XMIT_OK                = 0x00020101
- OID_GEN_RCV_OK                 = 0x00020102
- OID_GEN_XMIT_ERROR             = 0x00020103
- OID_GEN_RCV_ERROR              = 0x00020104
- OID_GEN_RCV_NO_BUFFER          = 0x00020105
- OID_802_3_PERMANENT_ADDRESS    = 0x01010101
- OID_802_3_CURRENT_ADDRESS      = 0x01010102
- OID_802_3_MULTICAST_LIST       = 0x01010103
- OID_802_3_MAXIMUM_LIST_SIZE    = 0x01010104

----------------------------------------------------
6) Current OID behavior in v45
----------------------------------------------------
QueryInformation highlights:
- OID_GEN_SUPPORTED_LIST:
  -> returns g_SupportedOids[]
- OID_GEN_HARDWARE_STATUS:
  -> NdisHardwareStatusReady
- OID_GEN_MEDIA_SUPPORTED / OID_GEN_MEDIA_IN_USE:
  -> NdisMedium802_3
- OID_GEN_MEDIA_CONNECT_STATUS:
  -> cached LinkState (Connected/Disconnected)
- OID_GEN_MAXIMUM_FRAME_SIZE:
  -> 1500
- OID_GEN_MAXIMUM_TOTAL_SIZE:
  -> 1514
- OID_GEN_LINK_SPEED:
  -> 10000000 (1 Gbps in 100 bps units)
- OID_GEN_VENDOR_ID:
  -> derived from MAC OUI (first 3 bytes)
- OID_GEN_VENDOR_DESCRIPTION:
  -> "Dietmar i219 XP skeleton v45"
- OID_GEN_DRIVER_VERSION:
  -> 0x0100
- OID_GEN_VENDOR_DRIVER_VERSION:
  -> 0x00010000 (1.0 encoded as major/minor)
- OID_GEN_MAC_OPTIONS:
  -> COPY_LOOKAHEAD_DATA | TRANSFERS_NOT_PEND (observed as 0x5)
- OID_GEN_MAXIMUM_SEND_PACKETS:
  -> 1
- OID_GEN_MAXIMUM_LOOKAHEAD:
  -> 1500
- OID_GEN_CURRENT_LOOKAHEAD / OID_GEN_CURRENT_PACKET_FILTER:
  -> returns cached values (Lookahead / PacketFilter)
- Basic stats OIDs:
  -> currently 0 (no counters yet)
- OID_802_3_PERMANENT_ADDRESS / CURRENT_ADDRESS:
  -> returns 6 bytes MAC
- OID_802_3_MAXIMUM_LIST_SIZE:
  -> 32

SetInformation highlights:
- OID_GEN_CURRENT_PACKET_FILTER:
  -> currently stores PacketFilter only (hardware filter mapping still in progress)
- OID_GEN_CURRENT_LOOKAHEAD:
  -> stores Lookahead (clamped to 1500)
- OID_802_3_MULTICAST_LIST:
  -> stores up to 32 multicast MACs (but MTA programming is still in progress)

----------------------------------------------------
7) Problems already solved
----------------------------------------------------
- Driver loads/starts (v45):
  -> Clean start in Device Manager, Initialize runs, MMIO mapping is real.
- Reliable MMIO/resource discovery:
  -> Stable BAR0 mapping confirmed (0xDF400000 / len 0x20000).
- Root cause of earlier NDIS crash identified:
  -> When I previously “faked” some OIDs via WinDbg, I triggered a crash in NDIS OID validation
     (bad/NULL/incorrect Supported-OID list handling).
  -> Fix direction implemented:
     - real SupportedOids[] array
     - real Query/Set OID engine with correct BUFFER_TOO_SHORT / BytesNeeded / BytesWritten.
- XP NDIS signature differences handled:
  -> Adjusted NdisMMapIoSpace / NdisMUnmapIoSpace usage for XP/NDIS5 compatibility.

----------------------------------------------------
8) What I still miss
----------------------------------------------------
Even though the driver starts and answers OIDs, I still do NOT have real network traffic working end-to-end:
- No DHCP lease / no real RX/TX  I can see.

What I believe is still needed:
1) Correct i219-family (PCH SPT) PHY + NVM init sequence (this is where i219 differs most from i218).
2) Correct mapping of OID_GEN_CURRENT_PACKET_FILTER into real hardware filtering (RCTL + tables).
3) Correct implementation of OID_802_3_MULTICAST_LIST into MTA programming (or safe fallback).
4) Possibly: switch from polled mode to proper interrupt mode once the basics work.

If anyone has experience with i219 on older OSes (XP/2003):
- The minimal “must-do” i219 (PCH SPT) PHY/NVM init steps to get stable link + RX/TX.
- Any known i219-specific register quirks that differ from i218-family.
- Confirmation whether my minimal TX/RX + RCTL strategy is sufficient, or which missing bits are typically required.

Dietmar

PS:

Where the technical details in my i219 XP driver thread come from, and how I verify everything with crazy WinDbg use.

----------------------------------------------------
A) Direct observations from MY system (WinDbg + runtime logging)
----------------------------------------------------
These facts are taken from my own XP test machine and WinDbg sessions:
- PCI ID: 8086:15B8 (Intel i219-V2)
- BAR0 MMIO mapping: base 0xDF400000, size 0x20000
- IRQ resources (legacy line/vector)
- MAC address read/used by the driver (70-85-C2-7E-28-B7)
- Which OIDs are queried by NDIS / TCPIP and what my driver returned (seen via breakpoints + stack inspection)
- Whether frames are actually TX/RX (currently: driver starts, but traffic still missing)

----------------------------------------------------
B) Extracted from my own driver source code (current v45 skeleton)
----------------------------------------------------
These items are not “guessed”; they come straight from my current i219.c / i219.h:
- The exact SupportedOids[] array (the list I return for OID_GEN_SUPPORTED_LIST)
- My current OID Query/Set behavior (what I return/store)
- Ring sizes / buffer sizes / the delayed bring-up strategy (late TX/RX init after 40s)
- Which register offsets I currently touch (RCTL/TCTL/TIPG/RDBAL… etc.) and which bits I set

----------------------------------------------------
C) Public reference sources (open headers/docs)
----------------------------------------------------
I used publicly available sources for “static” definitions, i.e. register offsets, bit masks, and OID semantics:

1) Intel e1000 / e1000e style register offsets + bit definitions
   - Linux kernel: drivers/net/ethernet/intel/e1000e/ (hw.h, defines.h, etc.)
   - QEMU’s e1000_hw.h (also includes the classic register layout)

2) NDIS OID numbers (hex values) and structures
   - ReactOS ntddndis.h (matches Windows OID values and is easy to reference)

3) OID semantics (what Windows expects)
   - Microsoft documentation for OID_GEN_SUPPORTED_LIST, OID_GEN_CURRENT_PACKET_FILTER,
     OID_802_3_MULTICAST_LIST, OID_GEN_LINK_SPEED, etc.

----------------------------------------------------
D) Heavy WinDbg use, the extremely hard part ;))
----------------------------------------------------
My main technique is breakpoint-driven “bisection” (binary search in control flow):
- Set a breakpoint at the function I expect to run.
- If it is NOT hit, move the breakpoint earlier (caller / dispatcher) until I find the last hit location.
- The bug must be between the last-hit BP and the first-not-hit BP.
- Only after I have narrowed it down do I inspect registers/stack/buffers.

Typical breakpoints I use:
1) OID path:
   bp i219!I219MiniportQueryInformation
   bp i219!I219MiniportSetInformation
   bp NDIS!ndisMDispatchRequest

   Inside Query/SetInformation on x86 NDIS5, the OID value is the 2nd argument:
   - OID is at [esp+8]
     ? poi(@esp+8)
   I often dump the full stack to see all arguments:
     dd esp L20
   Then continue:
     g

2) Driver bring-up / resources:
   bp i219!I219Initialize
   bp i219!I219LateBringUp
   bp i219!I219ProgramRxTx
   bp i219!I219WriteMacToRar0

3) RX/TX progress:
   bp i219!I219SendPackets
   bp i219!I219PollRxTx
   (then watch MMIO reads/writes and descriptor ring head/tail changes)

If an OID is queried and packets still don’t flow, I focus on:
- OID_GEN_CURRENT_PACKET_FILTER SET → must translate into RCTL + filtering (broadcast/multicast)
- OID_802_3_MULTICAST_LIST SET → must program MTA (or enable a safe fallback)
- Link state / PHY init (i219 “PCH SPT” path differs from i218 “LPT” path)

----------------------------------------------------
Reference links (for convenience)
----------------------------------------------------
Linux e1000e:
- https://github.com/torvalds/linux/tree/master/drivers/net/ethernet/intel/e1000e

QEMU e1000 register layout (e1000_hw.h):
- https://git.zx2c4.com/qemu/tree/hw/e1000_hw.h

ReactOS ntddndis.h (OID hex values):
- https://doxygen.reactos.org/dc/d38/ntddndis_8h.html

Microsoft OID docs:
- https://learn.microsoft.com/en-us/windows-hardware/drivers/network/oid-gen-supported-list
- https://learn.microsoft.com/en-us/windows-hardware/drivers/network/oid-gen-current-packet-filter
- https://learn.microsoft.com/en-us/windows-hardware/drivers/n

Edited by Dietmar
Posted (edited)
On 2/8/2026 at 12:05 PM, Dietmar said:

Hi,

I make a new nvme2k driver for XP SP3 based on scsiport via the idea for this driver from Dominik Behr.

The idea for to reach this, I get from Reactos scsi miniport driver.

Now it works also for to INSTALL XP SP3 direct to any nvme device.

Please test a lot

Dietmar

https://files.catbox.moe/duyf52.zip

 

Here is the Source Code of the only modded nvme2k.c for to direct install nvme scsi miniport of XP SP3 via nvme2k.sys

//
// SCSI Miniport Driver for Windows 2000
//

#include "nvme2k.h"
#include "utils.h"

// Poll interval for RequestTimerCall (ScsiPort expects microseconds)
#define NVME2K_POLL_USEC 10000

// --------------------------------------------------------------------------
// IRQ robustness for Win2000/XP (SCSIPORT): force legacy INTx by disabling MSI/MSI-X
// Many modern NVMe controllers come up with MSI-X enabled; XP SCSIPORT does not
// reliably support MSI/MSI-X, resulting in massive timeouts (SpTimeoutSynchronized...).
// --------------------------------------------------------------------------
static VOID NvmeForceLegacyIntx(IN PHW_DEVICE_EXTENSION DevExt)
{
    // PCI conventional header offsets
    const UCHAR PCI_STATUS_OFFSET_LOCAL   = 0x06; // USHORT
    const UCHAR PCI_CAP_PTR_OFFSET_LOCAL  = 0x34; // UCHAR
    const USHORT PCI_STATUS_CAP_LIST      = 0x0010;

    const UCHAR PCI_CAP_ID_MSI  = 0x05;
    const UCHAR PCI_CAP_ID_MSIX = 0x11;

    USHORT status;
    UCHAR  capPtr;
    UCHAR  capId;
    UCHAR  next;
    ULONG  guard;

    status = ReadPciConfigWord(DevExt, PCI_STATUS_OFFSET_LOCAL);
    if (!(status & PCI_STATUS_CAP_LIST)) {
        return;
    }

    capPtr = ReadPciConfigByte(DevExt, PCI_CAP_PTR_OFFSET_LOCAL);
    capPtr = (UCHAR)(capPtr & (UCHAR)~0x03); // DWORD alignment

    guard = 0;
    while (guard < 32 && capPtr >= 0x40 && capPtr < 0x100) {
        capId  = ReadPciConfigByte(DevExt, capPtr);
        next   = ReadPciConfigByte(DevExt, (UCHAR)(capPtr + 1));
        next   = (UCHAR)(next & (UCHAR)~0x03);

        if (capId == PCI_CAP_ID_MSI) {
            // MSI Message Control is a WORD at cap+2; bit0 = MSI Enable
            USHORT msiCtrl;
            USHORT newCtrl;

            msiCtrl = ReadPciConfigWord(DevExt, (UCHAR)(capPtr + 2));
            if (msiCtrl & 0x0001) {
                newCtrl = (USHORT)(msiCtrl & (USHORT)~0x0001);
                WritePciConfigWord(DevExt, (UCHAR)(capPtr + 2), newCtrl);
#ifdef NVME2K_DBG
                ScsiDebugPrint(0, "nvme2k: NvmeForceLegacyIntx - MSI disabled (cap=%02X ctrl %04X->%04X)\n",
                               capPtr, msiCtrl, newCtrl);
#endif
            }
        } else if (capId == PCI_CAP_ID_MSIX) {
            // MSI-X Message Control is a WORD at cap+2; bit15 = MSI-X Enable, bit14 = Function Mask
            USHORT msixCtrl;
            USHORT newCtrl;

            msixCtrl = ReadPciConfigWord(DevExt, (UCHAR)(capPtr + 2));
            newCtrl  = msixCtrl;

            // Mask vectors and disable MSI-X
            newCtrl = (USHORT)(newCtrl | 0x4000);           // Function Mask
            newCtrl = (USHORT)(newCtrl & (USHORT)~0x8000);  // MSI-X Enable

            if (newCtrl != msixCtrl) {
                WritePciConfigWord(DevExt, (UCHAR)(capPtr + 2), newCtrl);
#ifdef NVME2K_DBG
                ScsiDebugPrint(0, "nvme2k: NvmeForceLegacyIntx - MSI-X disabled (cap=%02X ctrl %04X->%04X)\n",
                               capPtr, msixCtrl, newCtrl);
#endif
            }
        }

        if (next == 0 || next == capPtr) {
            break;
        }

        capPtr = next;
        guard++;
    }
}

//
// DriverEntry - Main entry point
//
ULONG DriverEntry(IN PVOID DriverObject, IN PVOID Argument2)
{
    HW_INITIALIZATION_DATA hwInitData;
    ULONG status;
#if (_WIN32_WINNT < 0x500)
    ULONG HwContext[2];
#endif
    // Break into debugger if attached

#ifdef NVME2K_DBG
    //__asm { int 3 }
    ScsiDebugPrint(0, "nvme2k: DriverEntry called\n");
#endif

    // Zero out the initialization data structure
    memset(&hwInitData, 0, sizeof(HW_INITIALIZATION_DATA));

    // Set size of structure
    hwInitData.HwInitializationDataSize = sizeof(HW_INITIALIZATION_DATA);

    // Set entry points
    hwInitData.HwInitialize = HwInitialize;
    hwInitData.HwStartIo = HwStartIo;
    hwInitData.HwInterrupt = HwInterrupt;
    hwInitData.HwFindAdapter = HwFindAdapter;
    hwInitData.HwResetBus = HwResetBus;
#if (_WIN32_WINNT >= 0x500)
    hwInitData.HwAdapterControl = HwAdapterControl;
#else
    hwInitData.HwAdapterState = HwAdapterState;
#endif

    // Set driver-specific parameters
    hwInitData.AdapterInterfaceType = PCIBus;  // Change as needed
    hwInitData.DeviceExtensionSize = sizeof(HW_DEVICE_EXTENSION);
    hwInitData.SpecificLuExtensionSize = 0;
    hwInitData.SrbExtensionSize = sizeof(NVME_SRB_EXTENSION);  // Required for PRP list tracking
    hwInitData.NumberOfAccessRanges = 1;
    hwInitData.MapBuffers = TRUE;
    hwInitData.NeedPhysicalAddresses = TRUE;
    hwInitData.TaggedQueuing = TRUE;
    hwInitData.AutoRequestSense = TRUE;
    hwInitData.MultipleRequestPerLu = TRUE;

    // Vendor/Device IDs (for PCI devices)
    hwInitData.VendorIdLength = 0;
    hwInitData.VendorId = NULL;
    hwInitData.DeviceIdLength = 0;
    hwInitData.DeviceId = NULL;

#if (_WIN32_WINNT < 0x500)
    HwContext[0] = 0;
    HwContext[1] = 0;
#endif
    // Call port driver
    status = ScsiPortInitialize(DriverObject, Argument2,
                                &hwInitData, 
#if (_WIN32_WINNT >= 0x500)
                                NULL
#else
                                HwContext
#endif
                            );

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: DriverEntry exiting with status 0x%08X\n", status);
#endif
    return status;
}

ULONG HwFoundAdapter(
    IN PHW_DEVICE_EXTENSION DevExt,
    IN OUT PPORT_CONFIGURATION_INFORMATION ConfigInfo,
    IN PUCHAR pciBuffer)
{
    PACCESS_RANGE accessRange;
    SCSI_PHYSICAL_ADDRESS bar0;
    ULONG bar0tmp;
    ULONG barSize;
    ULONG tempSize;

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - found NVMe device VID=%04X DID=%04X at bus %d slot %d\n",
                   DevExt->VendorId, DevExt->DeviceId, DevExt->BusNumber, DevExt->SlotNumber);
#endif

    // Read subsystem IDs using helper function
    DevExt->SubsystemVendorId = ReadPciConfigWord(DevExt, PCI_SUBSYSTEM_VENDOR_ID_OFFSET);
    DevExt->SubsystemId = ReadPciConfigWord(DevExt, PCI_SUBSYSTEM_ID_OFFSET);

    // Enable PCI device decoding and bus mastering.
    // Do NOT leave PCI_INTERRUPT_DISABLE set here: on Win2000/XP ScsiPort setups frequently rely on legacy INTx.
    // (MSI/MSI-X is not guaranteed/available with ScsiPort.)
    {
        USHORT cmdReg = ReadPciConfigWord(DevExt, PCI_COMMAND_OFFSET);
        cmdReg |= (PCI_ENABLE_BUS_MASTER | PCI_ENABLE_MEMORY_SPACE);
        cmdReg = (USHORT)(cmdReg & ~PCI_INTERRUPT_DISABLE); // ensure INTx not disabled
        WritePciConfigWord(DevExt, PCI_COMMAND_OFFSET, cmdReg);
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - PCI Command Register = %04X (IntDis=%d)\n",
                       cmdReg, !!(cmdReg & PCI_INTERRUPT_DISABLE));
#endif
    }


    // Force legacy INTx on XP/2000 to avoid MSI/MSI-X related timeouts
    NvmeForceLegacyIntx(DevExt);

    // Read interrupt configuration from PCI config space
    // This is probably redundant on Win2K and can be ifdefed out
    {
        UCHAR interruptLine = ReadPciConfigByte(DevExt, PCI_INTERRUPT_LINE_OFFSET);
        UCHAR interruptPin = ReadPciConfigByte(DevExt, PCI_INTERRUPT_PIN_OFFSET);

#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - PCI Interrupt Line=%d Pin=%d\n",
                       interruptLine, interruptPin);
        ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - ConfigInfo BEFORE: BusInterruptLevel=%d Vector=%d Mode=%d\n",
                       ConfigInfo->BusInterruptLevel, ConfigInfo->BusInterruptVector, ConfigInfo->InterruptMode);
#endif

#if (_WIN32_WINNT < 0x500)
        // CRITICAL FOR NT4: When manually setting SystemIoBusNumber/SlotNumber,
        // SCSI port doesn't automatically query interrupt configuration from HAL.
        // We MUST set valid interrupt parameters or we'll get STATUS_INVALID_PARAMETER.
        // For PCI: BusInterruptLevel = interrupt line, mode = LevelSensitive
        if (interruptPin != 0 && interruptLine != 0 && interruptLine != 0xFF) {
            ConfigInfo->BusInterruptLevel = interruptLine;
            ConfigInfo->BusInterruptVector = interruptLine;
            ConfigInfo->InterruptMode = LevelSensitive;
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - Set interrupt from PCI config: Level=%d\n", interruptLine);
#endif
        } else {
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - WARNING: No valid PCI interrupt configured\n");
#endif
            // If no valid interrupt, still need to set something valid for NT4.
            // Use polling mode - but this might not work on NT4!
            ConfigInfo->BusInterruptLevel = 0;
            ConfigInfo->BusInterruptVector = 0;
        }
#else
        // Win2000/XP: leave interrupt routing to ScsiPort/HAL; do not override ConfigInfo here.
#endif
    }

    // Set the number of access ranges we're using (1 for BAR0)
    // NT4 may require this to be explicitly set for resource translation
    ConfigInfo->NumberOfAccessRanges = 1;

    ConfigInfo->MaximumTransferLength = 32u << NVME_PAGE_SHIFT;  // safe default
    ConfigInfo->NumberOfBuses = 1;
    ConfigInfo->ScatterGather = TRUE;
    ConfigInfo->Master = TRUE;
    ConfigInfo->CachesData = FALSE;
    ConfigInfo->AdapterScansDown = FALSE;
    ConfigInfo->Dma32BitAddresses = TRUE;
#if (_WIN32_WINNT >= 0x500)
    ConfigInfo->Dma64BitAddresses = TRUE;  // NVMe supports 64-bit addressing
#endif    
    ConfigInfo->MaximumNumberOfTargets = 2;  // Support TargetId 0 and 1
    ConfigInfo->NumberOfPhysicalBreaks = 511;  // PRP1 + PRP list (512 entries)
    ConfigInfo->AlignmentMask = 0x3;  // DWORD alignment
    ConfigInfo->NeedPhysicalAddresses = TRUE;  // Required for ScsiPortGetPhysicalAddress to work
    ConfigInfo->TaggedQueuing = TRUE;  // Support tagged command queuing
    ConfigInfo->MultipleRequestPerLu = TRUE;  // Allow multiple outstanding commands per LUN
    ConfigInfo->AutoRequestSense = TRUE;  // Automatically provide sense data on errors
    // Note: SrbExtensionSize must be set in HW_INITIALIZATION_DATA, not here

#ifdef NVME2K_DBG_EXTRA
    {
        ULONG a;
        accessRange = &((*(ConfigInfo->AccessRanges))[0]);
        for (a = 0; a < ConfigInfo->NumberOfAccessRanges; a++) {
            ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - range:%u start:%08X, length:%08X, inMemory:%d\n",
                           a, (ULONG)(accessRange->RangeStart.QuadPart),
                           accessRange->RangeLength,
                           accessRange->RangeInMemory);
            accessRange++;
        }
    }
#endif
    // Determine BAR0 / controller register range.
    // On Win2000/XP PnP paths, ScsiPort usually provides a translated AccessRange already.
    // Only fall back to PCI BAR probing ("BAR sizing dance") if the AccessRange is not populated.
    accessRange = &((*(ConfigInfo->AccessRanges))[0]);

    if (accessRange->RangeLength != 0 && accessRange->RangeStart.QuadPart != 0) {
        // PnP path: trust the provided resource assignment.
        accessRange->RangeInMemory = TRUE; // NVMe register space is MMIO
        DevExt->ControllerRegistersLength = accessRange->RangeLength;
    } else {
        // Non-PnP / textmode scan path: read BAR0 from PCI config and size it.
        bar0tmp = ReadPciConfigDword(DevExt, PCI_BASE_ADDRESS_0);
        bar0.HighPart = 0;
        bar0.LowPart = bar0tmp & 0xFFFFFFF0;
        if ((bar0tmp & 0x6) == 0x6) {
            bar0.HighPart = ReadPciConfigDword(DevExt, PCI_BASE_ADDRESS_1);
            if (bar0.HighPart) {
                ScsiDebugPrint(0, "nvme2k: BAR0 base=0x%08X%08X beyond 4GB, it may not end well on 32bit kernel\n",
                            bar0.HighPart,
                            bar0.LowPart);
            }
        }

    #if (_WIN32_WINNT >= 0x500 && !defined(ALPHA))
        accessRange->RangeStart = ScsiPortConvertUlongToPhysicalAddress(ScsiPortConvertPhysicalAddressToULongPtr(bar0));
    #else
        accessRange->RangeStart = ScsiPortConvertUlongToPhysicalAddress(bar0.LowPart);
    #endif
        if (bar0tmp & 0x1) {
            return SP_RETURN_ERROR;
        }
        accessRange->RangeInMemory = TRUE;

        // Size BAR0 only if we had to probe it ourselves.
        WritePciConfigDword(DevExt, PCI_BASE_ADDRESS_0, 0xFFFFFFFF);

        // Read back the modified value
        barSize = ReadPciConfigDword(DevExt, PCI_BASE_ADDRESS_0);

        // Restore original BAR value
        WritePciConfigDword(DevExt, PCI_BASE_ADDRESS_0, bar0tmp);
        accessRange->RangeLength = ~(barSize & 0xFFFFFFF0) + 1;

        DevExt->ControllerRegistersLength = accessRange->RangeLength;
    }



#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - BAR0 base=0x%08X size=0x%08X\n",
                   (ULONG)accessRange->RangeStart.QuadPart,
                   accessRange->RangeLength);
#endif

    // Validate the access range (required for NT4, optional for Win2K+)
    // This checks if the range is available and doesn't conflict with other devices
    if (!ScsiPortValidateRange(
            (PVOID)DevExt,
            ConfigInfo->AdapterInterfaceType,
            ConfigInfo->SystemIoBusNumber,
            accessRange->RangeStart,
            accessRange->RangeLength,
            (BOOLEAN)!accessRange->RangeInMemory)) {
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - ScsiPortValidateRange failed for BAR0\n");
#endif
        return SP_RETURN_ERROR;
    }

    // Map the controller registers
    DevExt->ControllerRegisters = ScsiPortGetDeviceBase(
        (PVOID)DevExt,
        ConfigInfo->AdapterInterfaceType,
        ConfigInfo->SystemIoBusNumber,
        accessRange->RangeStart,
        accessRange->RangeLength,
        (BOOLEAN)!accessRange->RangeInMemory);

    if (DevExt->ControllerRegisters == NULL) {
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - failed to map controller registers\n");
#endif
        return SP_RETURN_ERROR;
    }
#if 0    
// can be reported in newer OSes
    // Read controller capabilities to determine max queue size
    // This must be done here so we can set ConfigInfo->NumberOfRequests
    {
        ULONGLONG cap;
        USHORT mqes, maxQueueSize;

        cap = NvmeReadReg64(DevExt, NVME_REG_CAP);
        mqes = (USHORT)(cap & NVME_CAP_MQES_MASK);
        maxQueueSize = mqes + 1;  // MQES is 0-based

        // Limit to our maximum (what fits in one page)
        if (maxQueueSize > NVME_MAX_QUEUE_SIZE) {
            maxQueueSize = NVME_MAX_QUEUE_SIZE;
        }

        // Tell SCSI port driver how many outstanding requests we can handle
        // This prevents the OS from sending more requests than we can queue
        ConfigInfo->NumberOfRequests = maxQueueSize;

        ScsiDebugPrint(0, "nvme2k: HwFindAdapter - MQES=%u, setting NumberOfRequests=%u\n",
                       mqes, maxQueueSize);
    }
#endif

//
// Uncached memory size calculation:
// - Admin SQ: 4096 bytes (4KB aligned)
// - I/O SQ: 4096 bytes (4KB aligned)
// - Utility buffer / PRP list pool: (SgListPages pages * 4KB, page-aligned)
// - Admin CQ: 4096 bytes (4KB aligned)
// - I/O CQ: 4096 bytes (4KB aligned)
// Total: ~60KB with alignment
//

    // Allocate uncached memory block
    DevExt->SgListPages = 32;
    DevExt->UncachedExtensionSize = (NVME_PAGE_SIZE * (DevExt->SgListPages + 4 + 1));

    DevExt->UncachedExtensionBase = ScsiPortGetUncachedExtension(
        (PVOID)DevExt,
        ConfigInfo,
        DevExt->UncachedExtensionSize);

    if (DevExt->UncachedExtensionBase == NULL) {
        DevExt->SgListPages = 16;
        DevExt->UncachedExtensionSize = (NVME_PAGE_SIZE * (DevExt->SgListPages + 4 + 1));

        DevExt->UncachedExtensionBase = ScsiPortGetUncachedExtension(
            (PVOID)DevExt,
            ConfigInfo,
            DevExt->UncachedExtensionSize);

        if (DevExt->UncachedExtensionBase == NULL) {
    #ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - failed to allocate uncached memory\n");
    #endif
            return SP_RETURN_ERROR;
        }
    }

    // Get physical address of the entire uncached block
    tempSize = DevExt->UncachedExtensionSize;
    DevExt->UncachedExtensionPhys = ScsiPortGetPhysicalAddress(
        (PVOID)DevExt,
        NULL,
        DevExt->UncachedExtensionBase,
        &tempSize);
    
    // Zero out the entire uncached memory
    memset(DevExt->UncachedExtensionBase, 0, DevExt->UncachedExtensionSize);

    // Initialize allocator
    DevExt->UncachedExtensionOffset = 0;

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - allocated %u bytes of uncached memory at virt=%p phys=%08X%08X\n",
                   DevExt->UncachedExtensionSize, DevExt->UncachedExtensionBase,
                   (ULONG)(DevExt->UncachedExtensionPhys.QuadPart >> 32),
                   (ULONG)(DevExt->UncachedExtensionPhys.QuadPart & 0xFFFFFFFF));
#endif

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - success, returning SP_RETURN_FOUND\n");
#endif

    if (!NvmeSanitizeController(DevExt)) {
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwInHwFoundAdapteritialize - NvmeSanitizeController failed\n");
#endif
        return SP_RETURN_ERROR;
    }

    if (!NvmeInitializeController(DevExt)) {
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFoundAdapter - NvmeInitializeController failed\n");
#endif
        return SP_RETURN_ERROR;
    }

    // We need to update some of the config info now from the data we got from the controller.
    ConfigInfo->MaximumTransferLength = DevExt->MaxTransferSizeBytes;
    if (((ConfigInfo->MaximumTransferLength >> NVME_PAGE_SHIFT) - 1) < ConfigInfo->NumberOfPhysicalBreaks)
        ConfigInfo->NumberOfPhysicalBreaks = (ConfigInfo->MaximumTransferLength >> NVME_PAGE_SHIFT) - 1;

    return SP_RETURN_FOUND;
}

//
// HwFindAdapter - Locate and configure the adapter
//
ULONG HwFindAdapter(
    IN PVOID DeviceExtension,
    IN PVOID HwContext,
    IN PVOID BusInformation,
    IN PCHAR ArgumentString,
    IN OUT PPORT_CONFIGURATION_INFORMATION ConfigInfo,
    OUT PBOOLEAN Again)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;
    UCHAR pciBuffer[256];
    ULONG slotNumber;
    ULONG busNumber;
    UCHAR baseClass, subClass, progIf;
    ULONG bytesRead;
    BOOLEAN PNP = ConfigInfo->NumberOfAccessRanges != 0;


    // Defaults: keep polling fallback enabled until we prove legacy INTx is reliable.
    DevExt->FallbackTimerNeeded = 1;
    DevExt->InterruptCount = 0;
    if (HwContext) {
        busNumber = ((PULONG)HwContext)[0];
        slotNumber = ((PULONG)HwContext)[1];
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFindAdapter:%p called with HwContext - Bus=%d Slot=%d\n",
                       DeviceExtension, busNumber, slotNumber);
#endif
    } else {
        // Win2k, PnP gives us this directly
        busNumber = ConfigInfo->SystemIoBusNumber;
        slotNumber = ConfigInfo->SlotNumber;
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFindAdapter:%p called w/o HwContext - Bus=%d Slot=%d PNP=%d\n",
                       DeviceExtension, busNumber, slotNumber, PNP);
#endif
    }


    // PnP path (Win2000/XP): ScsiPort gives us the exact bus/slot to probe.
    // Do NOT scan other slots here, or you may confuse enumeration and waste time in textmode.
    if (!HwContext && PNP) {
        bytesRead = ScsiPortGetBusData(
            DeviceExtension,
            PCIConfiguration,
            busNumber,
            slotNumber,
            pciBuffer,
            256);

        if (bytesRead == 0) {
            *Again = FALSE;
            return SP_RETURN_NOT_FOUND;
        }

        DevExt->VendorId = *(USHORT*)&pciBuffer[PCI_VENDOR_ID_OFFSET];
        DevExt->DeviceId = *(USHORT*)&pciBuffer[PCI_DEVICE_ID_OFFSET];

        if (DevExt->VendorId == 0xFFFF || DevExt->VendorId == 0x0000) {
            *Again = FALSE;
            return SP_RETURN_NOT_FOUND;
        }

        DevExt->RevisionId = pciBuffer[PCI_REVISION_ID_OFFSET];
        progIf = pciBuffer[PCI_CLASS_CODE_OFFSET];
        subClass = pciBuffer[PCI_CLASS_CODE_OFFSET + 1];
        baseClass = pciBuffer[PCI_CLASS_CODE_OFFSET + 2];

#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwFindAdapter (PnP) - bus %d slot %d: VID=%04X DID=%04X Class=%02X%02X%02X\n",
                       busNumber, slotNumber, DevExt->VendorId, DevExt->DeviceId,
                       baseClass, subClass, progIf);
#endif

        if (!IsNvmeDevice(baseClass, subClass, progIf)) {
            *Again = FALSE;
            return SP_RETURN_NOT_FOUND;
        }

        DevExt->BusNumber = busNumber;
        DevExt->SlotNumber = slotNumber;
        *Again = FALSE;
        
        // Ensure ConfigInfo matches the adapter we found (needed for non-PnP/textmode/NT4 scan paths)
        ConfigInfo->AdapterInterfaceType = PCIBus;
        ConfigInfo->SystemIoBusNumber = busNumber;
        ConfigInfo->SlotNumber = slotNumber;
        return HwFoundAdapter(DevExt, ConfigInfo, pciBuffer);
    }

scanloop:
    // Read PCI configuration space for THIS slot only
    bytesRead = ScsiPortGetBusData(
        DeviceExtension,
        PCIConfiguration,
        busNumber,
        slotNumber,
        pciBuffer,
        256);

    if (bytesRead == 0) {
        // No device in this slot - tell SCSI port to keep scanning other slots
        goto scannext;
    }

    // Extract Vendor ID and Device ID
    DevExt->VendorId = *(USHORT*)&pciBuffer[PCI_VENDOR_ID_OFFSET];
    DevExt->DeviceId = *(USHORT*)&pciBuffer[PCI_DEVICE_ID_OFFSET];

    // Check for invalid vendor ID
    if (DevExt->VendorId == 0xFFFF || DevExt->VendorId == 0x0000) {
        // No valid device in this slot - tell SCSI port to keep scanning other slots
        goto scannext;
    }

    // Extract class code information
    DevExt->RevisionId = pciBuffer[PCI_REVISION_ID_OFFSET];
    progIf = pciBuffer[PCI_CLASS_CODE_OFFSET];
    subClass = pciBuffer[PCI_CLASS_CODE_OFFSET + 1];
    baseClass = pciBuffer[PCI_CLASS_CODE_OFFSET + 2];

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwFindAdapter - bus %d slot %d: VID=%04X DID=%04X Class=%02X%02X%02X\n",
                   busNumber, slotNumber, DevExt->VendorId, DevExt->DeviceId,
                   baseClass, subClass, progIf);
#endif

    // Check if this is an NVMe device
    if (IsNvmeDevice(baseClass, subClass, progIf)) {
        // Found an NVMe device at the slot SCSI port asked us to check!
        DevExt->BusNumber = busNumber;
        DevExt->SlotNumber = slotNumber;

        // Ensure ConfigInfo matches the adapter we found (needed for non-PnP/textmode/NT4 scan paths)
        ConfigInfo->AdapterInterfaceType = PCIBus;
        ConfigInfo->SystemIoBusNumber = busNumber;
        ConfigInfo->SlotNumber = slotNumber;
// Store next slot/bus so we can resume scanning on next call
        if (HwContext) {
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwFindAdapter - NT4: store HwContext to resume scanning\n");
#endif
            ((PULONG)HwContext)[0] = DevExt->BusNumber;
            ((PULONG)HwContext)[1] = DevExt->SlotNumber + 1;
            if (((PULONG)HwContext)[1] >= (PCI_MAX_DEVICES*PCI_MAX_FUNCTION)) {
                ((PULONG)HwContext)[1] = 0;
                ((PULONG)HwContext)[0]++;
            }
            *Again = TRUE;
        } else {
            *Again = FALSE;
        }
#ifdef NVME2K_DBG
        if (!HwContext) {
            ScsiDebugPrint(0, "nvme2k: HwFindAdapter - uh oh no HwContext! are we going to scan whole thing again?\n");
        }
#endif
        return HwFoundAdapter(DevExt, ConfigInfo, pciBuffer);
    }
#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwFindAdapter - not an NVMe device\n");
#endif

scannext:
    // NT4 or install time: Continue scanning the bus
    slotNumber++;
    if (slotNumber == (PCI_MAX_DEVICES*PCI_MAX_FUNCTION)) {
        busNumber++;
        slotNumber = 0;
        if (busNumber == 16) { // theoretically 256 but we arent going to waste cycles
            *Again = FALSE;
            return SP_RETURN_NOT_FOUND;
        }
    }
    goto scanloop;
}

//
// HwInitialize - Initialize the adapter
//
BOOLEAN HwInitialize(IN PVOID DeviceExtension)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwInitialize called\n");
#endif

    // Ensure legacy INTx is not disabled at PCI command level.
    // Some ScsiPort environments (especially textmode) may not use MSI/MSI-X reliably.
    {
        USHORT cmdReg = ReadPciConfigWord(DevExt, PCI_COMMAND_OFFSET);
        if (cmdReg & PCI_INTERRUPT_DISABLE) {
            cmdReg = (USHORT)(cmdReg & ~PCI_INTERRUPT_DISABLE);
            WritePciConfigWord(DevExt, PCI_COMMAND_OFFSET, cmdReg);
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwInitialize - cleared PCI_INTERRUPT_DISABLE (Cmd=%04X)\n", cmdReg);
#endif
        }
    }

    // Step 3: Enable interrupts
    // This is done after initialization is complete but before HwInitialize returns,
    // so ScsiPort knows we're interrupt-capable
    NvmeEnableInterrupts(DevExt);

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwInitialize finished successfully\n");
#endif
    return TRUE;
}

//
// HwStartIo - Process SCSI request
//
BOOLEAN HwStartIo(IN PVOID DeviceExtension, IN PSCSI_REQUEST_BLOCK Srb)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;
    NVME_COMMAND nvmeCmd;
    USHORT commandId;

#ifdef NVME2K_DBG_EXTRA
    ScsiDebugPrint(0, "nvme2k: HwStartIo called - Function=%02X Path=%d Target=%d Lun=%d\n",
                   Srb->Function, Srb->PathId, Srb->TargetId, Srb->Lun);
#endif

    // If interrupts are flaky/missing (common on modern PCIe with XP textmode),
    // arm a lightweight fallback timer that polls NVMe completions.
    // HwInterrupt() will cancel the timer whenever real interrupts fire.
    if (DevExt->InitComplete && DevExt->FallbackTimerNeeded) {
        ScsiPortNotification(RequestTimerCall, DeviceExtension, FallbackTimer, NVME2K_POLL_USEC);
    }

#if 1
    // Poll completion queues as a backup in case interrupts are delayed
    // This helps performance on busy systems
    if (DevExt->InitComplete) {
        if (DevExt->CurrentQueueDepth > 0 || DevExt->NonTaggedInFlight) {
            NvmeProcessAdminCompletion(DevExt);
            NvmeProcessIoCompletion(DevExt);
        }
    }
#endif

    // Check if the request is for our device (PathId=0, TargetId=0, Lun=0)
    if (Srb->PathId != 0 || Srb->TargetId != 0 || Srb->Lun != 0) {
        // Not our device - distinguish between invalid target and invalid LUN
        if (Srb->Function == SRB_FUNCTION_EXECUTE_SCSI) {
            // Check if this is an invalid LUN on our target (Path=0, Target=0, but Lun != 0)
            if (Srb->PathId == 0 && Srb->TargetId == 0 && Srb->Lun != 0) {
                // Invalid LUN on our target - return error with sense data
                PSENSE_DATA senseBuffer;

                Srb->SrbStatus = SRB_STATUS_ERROR;
                Srb->ScsiStatus = 0x02;  // CHECK_CONDITION

                // Fill in sense data if AutoRequestSense is enabled and buffer is available
                if (Srb->SenseInfoBuffer != NULL && Srb->SenseInfoBufferLength >= sizeof(SENSE_DATA)) {
                    senseBuffer = (PSENSE_DATA)Srb->SenseInfoBuffer;
                    memset(senseBuffer, 0, sizeof(SENSE_DATA));

                    senseBuffer->ErrorCode = 0x70;  // Current error, fixed format
                    senseBuffer->Valid = 0;
                    senseBuffer->SenseKey = SCSI_SENSE_ILLEGAL_REQUEST;
                    senseBuffer->AdditionalSenseLength = sizeof(SENSE_DATA) - 8;
                    senseBuffer->AdditionalSenseCode = SCSI_ADSENSE_INVALID_LUN;
                    senseBuffer->AdditionalSenseCodeQualifier = 0x00;

                    Srb->SrbStatus |= SRB_STATUS_AUTOSENSE_VALID;
                }
            } else {
                // Invalid target or path - selection timeout
                Srb->SrbStatus = SRB_STATUS_SELECTION_TIMEOUT;
            }
        } else {
            Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;
        }
        ScsiPortNotification(RequestComplete, DeviceExtension, Srb);
        ScsiPortNotification(NextRequest, DeviceExtension, NULL);
        return TRUE;
    }

    // Process the SRB based on its function
    switch (Srb->Function) {
        case SRB_FUNCTION_EXECUTE_SCSI:
#ifdef NVME2K_DBG_EXTRA
            ScsiDebugPrint(0, "nvme2k: processing op=%02X\n", Srb->Cdb[0]);

            // Log tagged queuing usage
            if (Srb->SrbFlags & SRB_FLAGS_QUEUE_ACTION_ENABLE) {
                const char* queueType = "Unknown";
                switch (Srb->QueueAction) {
                    case SRB_SIMPLE_TAG_REQUEST: queueType = "SIMPLE"; break;
                    case SRB_HEAD_OF_QUEUE_TAG_REQUEST: queueType = "HEAD_OF_QUEUE"; break;
                    case SRB_ORDERED_QUEUE_TAG_REQUEST: queueType = "ORDERED"; break;
                }
                ScsiDebugPrint(0, "nvme2k: Tagged queuing enabled - QueueAction=%s (0x%02X) Tag:%02X\n",
                               queueType, Srb->QueueAction, Srb->QueueTag);
            }
#endif
            // Process SCSI CDB
            switch (Srb->Cdb[0]) {
                case SCSIOP_READ6:
                case SCSIOP_READ:
                case SCSIOP_READ16:
                case SCSIOP_WRITE6:
                case SCSIOP_WRITE:
                case SCSIOP_WRITE16:
                    return ScsiHandleReadWrite(DevExt, Srb);
                    
                case SCSIOP_TEST_UNIT_READY:
                    if (DevExt->InitComplete)
                        Srb->SrbStatus = SRB_STATUS_SUCCESS;
                    else
                        Srb->SrbStatus = SRB_STATUS_BUSY;
                    break;

                case SCSIOP_VERIFY6:
                case SCSIOP_VERIFY:
                    Srb->SrbStatus = SRB_STATUS_SUCCESS;
                    break;
                    
                case SCSIOP_INQUIRY:
                    return ScsiHandleInquiry(DevExt, Srb);

                case SCSIOP_READ_CAPACITY:
                    return ScsiHandleReadCapacity(DevExt, Srb);

                case SCSIOP_READ_CAPACITY16:
                    return ScsiHandleReadCapacity16(DevExt, Srb);

                case SCSIOP_LOG_SENSE:
                    return ScsiHandleLogSense(DevExt, Srb);

                case SCSIOP_MODE_SENSE:
                case SCSIOP_MODE_SENSE10:
                    return ScsiHandleModeSense(DevExt, Srb);
                    
                case SCSIOP_START_STOP_UNIT:
                    // Accept but do nothing
                    Srb->SrbStatus = SRB_STATUS_SUCCESS;
                    break;
                    
                case SCSIOP_SYNCHRONIZE_CACHE:
                    return ScsiHandleFlush(DevExt, Srb);

                case SCSIOP_ATA_PASSTHROUGH16:
                case SCSIOP_ATA_PASSTHROUGH12:
                    // SAT (SCSI/ATA Translation) ATA PASS-THROUGH commands
                    return ScsiHandleSatPassthrough(DevExt, Srb);

                case SCSIOP_READ_DEFECT_DATA10:
                    return ScsiHandleReadDefectData10(DevExt, Srb);

                default:
#ifdef NVME2K_DBG
                    ScsiDebugPrint(0, "nvme2k: HwStartIo - unimplemented SCSI opcode 0x%02X\n", Srb->Cdb[0]);
#endif
                    Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;
                    break;
            }
            break;

        case SRB_FUNCTION_FLUSH:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo SRB_FUNCTION_FLUSH\n");
#endif
            return ScsiHandleFlush(DevExt, Srb);

        case SRB_FUNCTION_FLUSH_QUEUE:
            // No internal queue to flush - requests go directly to hardware
            Srb->SrbStatus = SRB_STATUS_SUCCESS;
            break;

        case SRB_FUNCTION_SHUTDOWN:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo - SRB_FUNCTION_SHUTDOWN - flushing cache\n");
#endif
            // Flush all cached writes before shutdown
            return ScsiHandleFlush(DevExt, Srb);

        case SRB_FUNCTION_ABORT_COMMAND:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo SRB_FUNCTION_ABORT_COMMAND\n");
#endif
            Srb->SrbStatus = SRB_STATUS_SUCCESS;
            break;

        case SRB_FUNCTION_RESET_BUS:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo SRB_FUNCTION_RESET_BUS\n");
#endif
            Srb->SrbStatus = SRB_STATUS_SUCCESS;
            break;

        case SRB_FUNCTION_RESET_DEVICE:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo SRB_FUNCTION_RESET_DEVICE\n");
#endif
            Srb->SrbStatus = SRB_STATUS_SUCCESS;
            break;

        case SRB_FUNCTION_IO_CONTROL:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo - SRB_FUNCTION_IO_CONTROL\n");
#endif
            if (Srb->DataTransferLength >= sizeof(SRB_IO_CONTROL)) {
                PSRB_IO_CONTROL srbControl = (PSRB_IO_CONTROL)Srb->DataBuffer;
                if (memcmp(srbControl->Signature, "NVME2KDB", 8) == 0) {
                    if (HandleIO_NVME2KDB(DevExt, Srb)) {
                        if (Srb->SrbStatus != SRB_STATUS_PENDING) {
                            Srb->SrbStatus = SRB_STATUS_SUCCESS;
                        }
                    } else {
                        Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;        
                    }
                } else if (memcmp(srbControl->Signature, "NvmeMini", 8) == 0) {
                    if (HandleIO_NvmeMini(DevExt, Srb)) {
                        if (Srb->SrbStatus != SRB_STATUS_PENDING) {
                            Srb->SrbStatus = SRB_STATUS_SUCCESS;
                        }
                    } else {
                        Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;        
                    }
                } else if (memcmp(srbControl->Signature, "SCSIDISK", 8) == 0) {
                    if (HandleIO_SCSIDISK(DevExt, Srb)) {
                        // If HandleIO_SCSIDISK returns TRUE, it may have set the status
                        // to PENDING for async operations.
                        if (Srb->SrbStatus != SRB_STATUS_PENDING) {
                            Srb->SrbStatus = SRB_STATUS_SUCCESS;
                        }
                    } else {
                        Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;        
                    }
                } else {
                    Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;    
                }
            } else {
#ifdef NVME2K_DBG
                ScsiDebugPrint(0, "nvme2k: HwStartIo - SRB_FUNCTION_IO_CONTROL invalid transfer length - DataTransferLength=%u\n",
                            Srb->DataTransferLength);
#endif
                Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;
                return FALSE;
            }
            break;

        default:
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: HwStartIo - unimplemented SRB function 0x%02X\n", Srb->Function);
#endif
            Srb->SrbStatus = SRB_STATUS_INVALID_REQUEST;
            break;
    }

    // Complete the request if not pending
    if (Srb->SrbStatus != SRB_STATUS_PENDING) {
        ScsiPortNotification(RequestComplete, DeviceExtension, Srb);
        ScsiPortNotification(NextRequest, DeviceExtension, NULL);
    }

    return TRUE;
}

VOID FallbackTimer(IN PVOID DeviceExtension)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;

    DevExt->FallbackTimerNeeded++;
    if (!DevExt->FallbackTimerNeeded) // wraparound
        DevExt->FallbackTimerNeeded = 2; // because 1 means fallbacktime didnt fire

    NvmeProcessAdminCompletion(DevExt);
    NvmeProcessIoCompletion(DevExt);

    // Rearm polling while requests are still in flight and fallback is enabled.
    // If real interrupts fire, HwInterrupt() cancels the timer.
    if (DevExt->InitComplete && DevExt->FallbackTimerNeeded) {
        if (DevExt->CurrentQueueDepth > 0 || DevExt->NonTaggedInFlight) {
            ScsiPortNotification(RequestTimerCall, DeviceExtension, FallbackTimer, NVME2K_POLL_USEC);
        }
    }
}


//
// HwInterrupt - ISR for adapter
//
BOOLEAN HwInterrupt(IN PVOID DeviceExtension)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;
    BOOLEAN interruptHandled = FALSE;

    // Process Admin Queue completions first
    if (NvmeProcessAdminCompletion(DevExt)) {
        interruptHandled = TRUE;
    }

    // Process I/O Queue completions
    if (NvmeProcessIoCompletion(DevExt)) {
        interruptHandled = TRUE;
    }

    // Only treat this as a "real" interrupt if we actually consumed NVMe completions.
    // This avoids disabling the polling fallback on shared/spurious IRQs.
    if (interruptHandled) {
        DevExt->InterruptCount++;

        if (DevExt->FallbackTimerNeeded) {
            // cancel any pending fallback timer
            ScsiPortNotification(RequestTimerCall, DeviceExtension, FallbackTimer, 0);

            // interrupts worked a million times, and callback didn't fire -> probably don't need a fallback
            if (DevExt->InterruptCount >= 1000000 && DevExt->FallbackTimerNeeded == 1) {
                DevExt->FallbackTimerNeeded = 0;
            }
        }
    }

    return interruptHandled;
}


//
// HwResetBus - Reset the SCSI bus
//
BOOLEAN HwResetBus(IN PVOID DeviceExtension, IN ULONG PathId)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;

    // TODO: Reset the SCSI bus
    // Perform hardware reset

    // Complete all outstanding requests
    ScsiPortCompleteRequest(DeviceExtension, (UCHAR)PathId, 
                           SP_UNTAGGED, SP_UNTAGGED,
                           SRB_STATUS_BUS_RESET);

    return TRUE;
}

#if (_WIN32_WINNT >= 0x500)
//
// HwAdapterControl - Handle adapter power and PnP events (Windows 2000+)
//
SCSI_ADAPTER_CONTROL_STATUS HwAdapterControl(
    IN PVOID DeviceExtension,
    IN SCSI_ADAPTER_CONTROL_TYPE ControlType,
    IN PVOID Parameters)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;
    SCSI_ADAPTER_CONTROL_STATUS status = ScsiAdapterControlSuccess;

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwAdapterControl called - ControlType=%d\n", ControlType);
#endif
    switch (ControlType) {
        case ScsiQuerySupportedControlTypes:
            {
                PSCSI_SUPPORTED_CONTROL_TYPE_LIST list =
                    (PSCSI_SUPPORTED_CONTROL_TYPE_LIST)Parameters;

                // Indicate which control types we support
                list->SupportedTypeList[ScsiStopAdapter] = TRUE;
                list->SupportedTypeList[ScsiRestartAdapter] = TRUE;
            }
            break;

        case ScsiStopAdapter:
            // Stop the adapter - perform clean shutdown
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: ScsiStopAdapter - performing shutdown\n");
#endif
            NvmeShutdownController(DevExt);
            break;

        case ScsiRestartAdapter:
            // Restart the adapter - reinitialize controller
#ifdef NVME2K_DBG
            ScsiDebugPrint(0, "nvme2k: ScsiRestartAdapter - reinitializing\n");
#endif
            // Controller was reset, need to reinitialize
            if (HwInitialize(DevExt)) {
                status = ScsiAdapterControlSuccess;
            } else {
                status = ScsiAdapterControlUnsuccessful;
            }
            break;

        default:
            status = ScsiAdapterControlUnsuccessful;
            break;
    }

    return status;
}
#else
//
// HwAdapterState - Handle adapter state changes (Windows NT 4)
//
BOOLEAN HwAdapterState(
    IN PVOID DeviceExtension,
    IN PVOID Context,
    IN BOOLEAN SaveState)
{
    PHW_DEVICE_EXTENSION DevExt = (PHW_DEVICE_EXTENSION)DeviceExtension;

#ifdef NVME2K_DBG
    ScsiDebugPrint(0, "nvme2k: HwAdapterState called - SaveState=%d\n", SaveState);
#endif

    if (SaveState) {
        // Save adapter state - prepare for power down or hibernation
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwAdapterState - saving state and shutting down\n");
#endif
        // Perform clean shutdown of the NVMe controller
        NvmeShutdownController(DevExt);
    } else {
        // Restore adapter state - reinitialize after power up
#ifdef NVME2K_DBG
        ScsiDebugPrint(0, "nvme2k: HwAdapterState - restoring state\n");
#endif
        // Reinitialize the controller
        return HwInitialize(DevExt);
    }
    return TRUE;
}
#endif
 

 

Can you also please create PR with these changes for everyone to main repo? https://github.com/techomancer/nvme2k

Edited by George King
Posted

@George King

Hi,

I dont know, how to do this "Can you also please create PR with these changes for everyone to main repo?".

My new driver nvme2k.sys is stable for XP SP3,

I work now with it on daily use

Dietmar

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