A "PCI Device" appearing as an unknown device usually means Windows 11 has detected the hardware but cannot identify it because the appropriate driver is missing. Common physical components that show up as a "PCI Device" include:

Sometimes simply refreshing the connection allows Windows to recognize the device correctly.

Here are some common issues you may encounter with PCI device drivers on Windows 11:

PCM_DEVICE_EXTENSION devExt = GetDeviceExtension(Device); ULONG i; PCM_PARTIAL_RESOURCE_DESCRIPTOR desc; for (i = 0; i < WdfCmResourceListGetCount(ResourcesTranslated); i++) desc = WdfCmResourceListGetDescriptor(ResourcesTranslated, i); if (desc->Type == CmResourceTypeMemory) // Map BAR devExt->BarBase = (PUCHAR)MmMapIoSpace( desc->u.Memory.Start, desc->u.Memory.Length, MmNonCached );