Display artifacts on bootloader -> kernel transition with xe

Apparently with xe, the initial framebuffer is not working as well as it should. I'm testing on the same machine with xe or i915 and comparing the output. I recorded 2 videos to show the artifacts as well as the dmesg.

This is with TGL, but I also see the same thing on an ADL-N with HDMI. It doesn't seem to be related to the display type but rather how the allocation is done for initial fb.

dmesg.xe.log / dmesg.i915.log

video xe booting / video i915 booting

This was with the just released 6.11. Also reproducible with drm-tip from today. The last time I remember not seeing such artifacts was on 6.7 or 6.8.

Tagging some people here... @jani / @rodrigovivi / @vsyrjala

Cc: @mlankhorst

Yeah, it seems we started allocating a bunch of stuff into GGTT before display had a chance to preserve the framebuffer.

Any allocation, like for UC, etc.. leads to display corruption. I have a patch to fix the offenders, and I'll add a patch to WARN if we try to add new allocations again.

https://patchwork.freedesktop.org/series/139215/

mentioned in issue #3575 (closed)

@mlankhorst Is this patch series merged ? There is a bug reported #3575 (closed) as linked by @mwa

Unfortunately not. There's a followup series that has some changes. Unfortunately because it touches so many different parts of the init sequence it's hard to get reviews for all parts simultaneously.