Driver uninstallation issues

[Troy Crosley <troycrosley@xxxxxxxxx>]

In Windows 10 version 2004, The coinstallers' DIF_INSTALLDEVICE routines do not get called on driver uninstall (via e.g. Apps & Features). In previous versions of Windows, this occurs as part of the uninstall during the null device install and is the only time DifRemove gets called to perform cleanup. We found a workaround by calling DifRemove (in the case of null drivers) from DIF_SELECTBESTCOMPATDRV, which is the only coinstaller request that seems to happen on uninstall in Windows 10 version 2004. I am wondering if there's a better way to address this issue that would be appropriate for the Xen Project.

I also found that the null driver detection in DIF_INSTALLDEVICE is insufficient (I last tested it on Windows 10 version 1803), causing DifInstall to be called rather than DifRemove during null driver installation. Specifically, DriverInfoAvailable gets set to TRUE rather than FALSE as expected for null drivers. I worked around this issue by additionally checking to see if DriverInfoData.DriverType was equal to SPDIT_CLASSDRIVER or SPDIT_COMPATDRIVER.

Troy