Start Me Up

I tried to make my own driver unloadable first, because this should be easier than unloading vga.sys. When the user tries to remove the graphics circuit from the device manager, then my driver receives the following IRPs: DispatchPnP gets called with: IRP_MJ_PNP IRP_MN_QUERY_DEVICE_RELATIONS RemovalRelations DispatchPnP does: create a list with 1 entry (the DeviceObject it received) call IofCompleteRequest DispatchPnP returns: STATUS_SUCCESS DispatchPnP gets called with: IRP_MJ_PNP IRP_MN_QUERY_REMOVE_DEVICE DispatchPnP does: IRP.IoStatus.Status = STATUS_SUCCESS call IofCompleteRequest DispatchPnP returns: STATUS_SUCCESS DispatchPnP gets called with: IRP_MJ_PNP IRP_MN_REMOVE_DEVICE DispatchPnP does: call DispatchPnP of videoprt.sys DispatchPnP returns: STATUS_SUCCESS DispatchPnP gets called with: IRP_MJ_PNP IRP_MN_QUERY_DEVICE_RELATIONS RemovalRelations DispatchPnP does: create a list with 1 entry (the DeviceObject it received) call IofCompleteRequest DispatchPnP returns: STATUS_SUCCESS DispatchPnP gets called with: IRP_MJ_PNP IRP_MN_QUERY_REMOVE_DEVICE DispatchPnP does: IRP.IoStatus.Status = STATUS_SUCCESS call IofCompleteRequest DispatchPnP returns: STATUS_SUCCESS DispatchPnP gets called with: IRP_MJ_PNP IRP_MN_CANCEL_REMOVE_DEVICE DispatchPnP does: call DispatchPnP of videoprt.sys DispatchPnP returns: STATUS_INVALID_DEVICE_STATE Afterwards the display is removed from the device manager but the graphics circuit is still there. Also, the device manager asks for a restart to complete the removal. So I think for the display the process is: QUERY_DEVICE_RELATIONS -> QUERY_REMOVE_DEVICE -> REMOVE_DEVICE And for the graphics circuit the process is: QUERY_DEVICE_RELATIONS -> QUERY_REMOVE_DEVICE -> CANCEL_REMOVE_DEVICE For some unknown reason Windows decides not to continue with the graphics circuit removal process.

.

I do not have an external graphics card to test your theory. The integrated graphics circuits I have can't be removed from the system, because they are a subcircuit of the chipset or the processor. If the vga.sys driver is still blocking the system from going into sleep because it's still running in the background, is it still possible somehow to remove the blockade? Edit: I think what I need to do, is basicly to find a save and clean way to unload vga.sys and make sure it gets loaded again if my driver gets unloaded. Well, thank you @jumper. I think you gave me the crucial information I was missing.

Hello developers, in Windows 2000 we have the situation, that if there is a non-plug-and-play-capable driver active, then the shutdown options "standby" and "hibernation" are not available. For example the driver vga.sys of Windows 2000 prevents the system from going into standby mode. When vga.sys is replaced with a plug-and-play-capable driver by installing one and then restarting, then the power options are available. My graphics driver is capable of performing mode switching and turning off the display after a certain time of inactivity directly after the installation. But the additional power options are only available after the user has restarted the computer. videoprt.sys and my driver do not receive any IRP_MJ_POWER queries until the system has been restarted. When I try to enter the standby mode manually by calling ntdll.dll/NtSetSystemPowerState before the reboot I get a STATUS_CANCELLED and a STATUS_SUCCESS after the reboot. I am out of ideas about what the operating system is waiting for and why it needs the restart. Does anyone have an idea what the problem could be? Many thanks.