Setup: I use reverse PRIME with a primary intel and a secondary nouveau card. I have enabled one output on each of the cards. The reverse PRIME (nouveau) output is set as primary output via xrandr.

Whenever there's a DRI user on the reverse PRIME screen, the following message gets written to my kernel log once for each buffer swap:

[drm:drm_wait_vblank [drm]] *ERROR* Unsupported type value 0x7d, supported mask 0x7400003f

Both DRI2 and DRI3 cause this behaviour.

Depending on the exact setup (DRI2/DRI3, different DRI users), I also get slightly different messages:

[drm:drm_wait_vblank [drm]] *ERROR* Unsupported type value 0x15d, supported mask 0x7400003f
[drm:drm_wait_vblank [drm]] *ERROR* Unsupported type value 0x400015d, supported mask 0x7400003f


Hardware:

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: NVIDIA Corporation GF119M [Quadro NVS 4200M] (rev a1)