On 10/02/2021 08:20, Nicolin Chen wrote:

Hi Guillaume,

On Sat, Feb 06, 2021 at 01:40:13PM +0000, Guillaume Tucker wrote:

quoted

quoted

It'd be nicer if I can get both logs of the vanilla kernel (failing)
and the commit-reverted version (passing), each applying this patch.

Sure, I've run 3 jobs:

* v5.11-rc6 as a reference, to see the original issue:
  https://lava.collabora.co.uk/scheduler/job/3187848

* + your debug patch:
  https://lava.collabora.co.uk/scheduler/job/3187849

* + the "breaking" commit reverted, passing the tests:
  https://lava.collabora.co.uk/scheduler/job/3187851

Thanks for the help!

I am able to figure out what's probably wrong, yet not so sure
about the best solution at this point.

Would it be possible for you to run one more time with another
debugging patch? I'd like to see the same logs as previous:
1. Vanilla kernel + debug patch
2. Vanilla kernel + Reverted + debug patch

As it turns out, next-20210210 is passing all the tests again so
it looks like this got fixed in the meantime:

  https://lava.collabora.co.uk/scheduler/job/3210192
  https://lava.collabora.co.uk/results/3210192/0_igt-kms-tegra

And here's a more extensive list of IGT tests on next-20210211,
all the regressions have been fixed:

  https://kernelci.org/test/plan/id/60254c42f51df36be53abe62/


I haven't run a reversed bisection to find the fix, but I guess
it wouldn't be too hard to find out what happened by hand anyway.
I see the drm/tegra/for-5.12-rc1 tag has been merged into
linux-next, maybe that solved the issue?

FYI I've also run some jobs with your debug patch and with the
breaking patch reverted:

  https://lava.collabora.co.uk/scheduler/job/3210245
  https://lava.collabora.co.uk/scheduler/job/3210596

Meanwhile I'll see what can be done to improve the automated
bisection so if there are new IGT regressions they would get
reported earlier.  I guess it would have saved us all some time
if it had been bisected in December.

Thanks,
Guillaume