Dear Maintainer,

At the newest releases Mesa by default no longer supports DRI2,
but at xorg-server-intel DRI2 still is the default.

If the legacy-x11 MESA-option is not set to dri2 at compilation
of Mesa ,then Xorg is showing an almost empty screen, which is not
accessible by mouse-click or keyboard. No error is shown.

I didnot succeed to force enabling DRI3 by setting
Option "DRI" "3" at xorg.conf, because the delivered package
xserver-xorg-video-intel at Debian is dated 20210115 and
it is missing commit
https://gitlab.freedesktop.org/xorg/driver/xf86-video-
intel/-/commit/2b552ed7d528d24b688b992a5164e062827d0ccb
: sna: Allow DRI3 on gen2/3 . Therefore the package does not enable DRI3, if
gen < 40.

In fact also the defult should be changed as requested at
https://gitlab.freedesktop.org/xorg/driver/xf86-video-intel/-/issues/229

I think modesetting could be a good alternative, also for non-Intel gpus.
But at the moment it is not, because glamor is working poorly.
GL 2.1 needs 128 gpu-instructions (i915g has a max of 64),
ES2.0 is very buggy and unusable.
Without glamor software rendering (LLVM) will be used.
I described this at
https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1636#note_2733371
.

The problem is enlarged by the Mesa-implementation, which is not giving
an errormessage that DRI2 is not supported. I also have no idea how
distributors should use the legacy-x11 compiler-option.

The fix at
https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1636 is
a heavy backport-fix, It is now 4 months waiting for any action.
Because of experience with merging-times at the previous glamor
fixes at Xwayland I am afraid, this fixes will be done far too late.

The problem is known and solutions at Xorg are available. It would be nice
that end-users do not get trouble because of missing DRI2.

A new snapshot of xf86-video-intel would solve the problem.