[Intel-gfx] Bay Trail: CPU C-state / GPU-freq changes interaction problems

[Hans de Goede]

Hi Chris, Ville,

I know that you've been looking into $subject lately. AFAIK you've
gotten some progress, but you are still sometimes seeing hangs in your
testing, right?

Several people who are following:
https://bugzilla.kernel.org/show_bug.cgi?id=109051

Have been testing two patches of mine which are a rough attempt at
fixing this. One makes the code change the GPU-freq less frequently
and as such is probably superseded by your work on this.

The other patch disables the CPU C6 C-state (while keeping C7), because
many errata mention issues with C6. Various people have reported good
results with that patch, even in cases where the GPU-freq related patch
does not help. The patch is here:
https://bugzilla.kernel.org/attachment.cgi?id=260585

Perhaps you can add this to your test workload and see if then the
hangs you are seeing do completely go away?

Regards,

Hans