Hi, On 2/10/21 1:48 PM, Chris Wilson wrote: > Quoting Hans de Goede (2021-02-10 10:37:19) >> Hi, >> >> On 2/10/21 12:07 AM, Chris Wilson wrote: >>> Quoting Hans de Goede (2021-02-09 11:46:46) >>>> Hi, >>>> >>>> On 2/9/21 12:27 AM, Chris Wilson wrote: >>>>> 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. >>>> >>>> Note the original / first reporter of: >>>> >>>> https://bugzilla.redhat.com/show_bug.cgi?id=1925346 >>>> >>>> Is using hsw-gt2, so it seems that the problem is not just the enabling of >>>> the mitigations on ivy-bridge / bay-trail but that there actually is >>>> a regression on devices where the WA worked fine before... >>> >>> There have been 3 crashes uploaded related to v5.10.9, and in all 3 >>> cases the ACTHD has been in the first page. This strongly suggests that >>> the w/a is scribbling over address 0. And there's then a very good >>> chance that >>> >>> commit 29d35b73ead4e41aa0d1a954c9bfbdce659ec5d6 >>> Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> >>> Date: Mon Jan 25 12:50:33 2021 +0000 >>> >>> drm/i915/gt: Always try to reserve GGTT address 0x0 >>> >>> commit 489140b5ba2e7cc4b853c29e0591895ddb462a82 upstream. >>> >>> in v5.10.14 is sufficient to hide the issue. >> >> That one actually is already in v5.10.13 and the various reportes of these >> issues have already tested 5.10.13. They did mention that it took longer >> to reproduce with 5.10.13 then with 5.10.10, but that could also be due to: >> >> "drm/i915/gt: Clear CACHE_MODE prior to clearing residuals" >> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=520d05a77b2866eb4cb9e548e1d8c8abcfe60ec5 > > Started looking for scratch page overwrites, and found this little gem: > https://patchwork.freedesktop.org/patch/420436/?series=86947&rev=1 > > Looks promising wrt the cause of overwriting random addresses -- and > I hope that is the explanation for the glitches/hangs. I have a hsw gt2 > with gnome shell, piglit is happy, but I suspect it is all due to > placement and so will only occur at random. If you can give me a list of commits to cherry-pick then I can prepare a Fedora 5.10.y kernel which those added for the group of Fedora users who are hitting this to test. FWIW those users have reported back that the 3 reverts which I mentioned earlier do indeed restore normal functionality (without glitches) for them. Regards, Hans
