On 2/25/21 1:33 PM, Justin Forbes wrote:
On Thu, Feb 25, 2021 at 5:44 AM Hans de Goede
> On 2/23/21 6:25 PM, Hans de Goede wrote:
>> I've been working with various reporters to try and get the sometimes severe
>> gfx glitches which people are seeing with kernel >= 5.10.9 resolved, see the
>> following bugs:
>> 1843274 - i915 GPU Hang with kernel 5.7 on Haswell (Acer C720P Chromebook)
>> 1925346 - Screen glitches after updating to Kernel 5.10.10
>> 1925903 - Flickering UI elements, screen instability (Wayland)
>> 1931065 - Frequent i915 hangs
>> I've written 2 patches 2 address this and asked users to test Fedora-kernel
>> scratch-builds with those patches added.
>> The first patch is i915-revert.patch, this reverts 3 troublesome commits
>> which were first added in 5.10.9 these commit change the i915 mitigations
>> for a year old i915 CVE which IIRC was mostly about data leaking from a
>> previous GPU context to the next. These patches enable these mitigations
>> on more GPU models, where they were previously disabled because they were
>> causing issues...
>> Reporters have reported a 100% success-rate in getting rid of the gfx
>> issues with these 3 reverts.
>> The second patch is i915-fixes.patch, this cherry-picks 3 patches from
>> -next instead (these were suggested by i915 upstream) and this also helps
>> for most users, but some users still report some rendering artifacts
>> (but overall things are much better).
>> Upstream has gone silent on the issue of there still being rendering
>> artifacts with the 3 cherry-picked fixes unfortunately.
>> Given that we are getting more and more bug-reports about this I think
>> that we should be do something about this downstream. Upstream seams
>> to be aiming for fixing things, rather then reverting, so going with
>> i915-fixes.patch will stay the closest to what I expect to land in
>> 5.10.y and 5.11.y at some point.
> The bug reports for this keep coming in; and it seems that this is
> fully resolved for all reporters except one by the i915-fixes.patch which
> I attached earlier; and for the one reporter who is still seeing some
> rendering glitches things are much improved, so I think he is also
> hitting a different issue.
> Here is the full lists of bugs which I'm aware of which all have this
> as root cause:
> 1843274 - i915 GPU Hang with kernel 5.7 on Haswell (Acer C720P Chromebook)
> 1922511 - Recent upgrades caused smearing/tearing
> 1925346 - Screen glitches after updating to Kernel 5.10.10
> 1925903 - Flickering UI elements, screen instability (Wayland)
> 1931065 - Frequent i915 hangs
> So unless there are any objections I would really like to move forward
> with adding i915-fixes.patch to the Fedora 5.10.y kernels.
The actual patch was not attached,
It was attached to the first email in this thread, I've also attached it
to this email again.
so I could not add it, you are
welcome to do so, or attach the patch and I will do it.
If you can take care of this, then that would be great, thanks.
Please also link bug 1925346 in the bodhi-update for the kernel where
this lands, I've dupped all the others to that bug.
kernels are managed in dist-git right now and follow the regular
process. 5.11 kernels are in the kernel-ark tree in the fedora-5.11
branch, I can handle an MR against this.
I know, I plan to submit my first 5.11 MR for the platform-profile
backport discussed in another thread soonish.
> Note I'm also working on getting the 3 -next commits:
> e627d5923cae ("drm/i915/gt: One more flush for Baytrail clear residuals")
> d30bbd62b1bf ("drm/i915/gt: Flush before changing register state")
> 1914911f4aa0 ("drm/i915/gt: Correct surface base address for renderclear")
> which are in i915-fixes.patch added to Greg's stable kernels.
Unfortunately only the first commit made it into Linus tree ATM, so
carrying these 3 downstream for now would be good. I've pinged Chris Wilson
about getting the other 2 send out in a fixes pull-req for 5.12 .