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I have written a KMDF function driver that uses the 1394 OHCI bus driver and I need access the some hardware registers to my PCIe device. The resources appear in Device Manager but are never are passed into the EvtDevicePrepareHardware so that I can access them. I also tried WdfFdoQueryForInterface using the GUID_BUS_INTERFACE_STANDARD and it returned unsupported.
Any ideas of why the bus driver doesn't allow me access to the HW resources from my function driver? Any way to work around this?
Thanks.
Are you installing the driver on the PCI device itself? how are you installing the driver? If you are calling devcon install [....] you are installing your driver on a root enumerated device and need to call devcon update [....] instead.
The device is a 1394 PCIe card. I assume the driver stack looks like PCIe->1394 OHCI->My Driver.
The driver is installed using PnpUtil using the -i and -a arguments. The driver is fully functional and has passed WHQL. I only discovered the resource issue because I need to add a feature that requires access to the registers.
To confirm, you are writing a driver that controls the 1394 OHCI controller itself, not a downstream 1394 device attached to the controller. If yes, it is quite odd that you don't see the assigned translated resource list passed to PrepareHardware but you do see them in device manager. What does !devnode <your device node> 0xE report for the assigned resources? You can find your dev node pointer by running !devnode 0 1 <name of your driver, do not include the .sys extension>.
Yes that's correct. Just to clarify, In Device Manager I see the resources in the 1394 OHCI Host controller driver resources tab but not in my driver.
I'll check that.