[Intel-gfx] [5.10.y regression] i915 clear-residuals mitigation is causing gfx issues

[Chris Wilson]

Quoting Hans de Goede (2021-02-08 20:38:58)
> Hi All,
> 
> We (Fedora) have been receiving reports from multiple users about gfx issues / glitches
> stating with 5.10.9. All reporters are users of Ivy Bridge / Haswell iGPUs and all
> reporters report that adding i915.mitigations=off to the cmdline fixes things, see:

I tried to reproduce this on the w/e on hsw-gt1, to no avail; and piglit
did not report any differences with and without mitigations. I have yet
to test other platforms. So I don't yet have an alternative. Though note
that v5.11 and v5.12 will behave similarly, so we need to urgently find
a fix for Linus's tree anyway.
-Chris