Submit_TextureWithPose is unimplemented

[frostworx]

With Submit_TextureWithPose being unimplemented in
https://github.com/ValveSoftware/Proton/tree/proton_5.0/vrclient_x64/vrclient_x64
several games refuse to work correctly in SteamVR for linux.
I know of at least two:
One is
L.A. Noire: The VR Case Files (722230): #3701
the other is
Grand Theft Auto V (271590): #37
or better say the GTA5 VR mod by @LukeRoss00
https://github.com/LukeRoss00/gta5-real-mod

Both games work normally on Desktop but HMD only has a black screen.
While the games are running the logs are filled with
fixme:vrclient:ivrcompositor_submit_dxvk Unhandled flags 0x8

Would be great if we could get GTA V in VR on linux with this feature being implemented.

[frostworx]

fyi, the Red Dead Redemption 2 VR mod (Patreon) requires the function Submit_TextureWithPose as well.