[bisected]: Games crash with 6.9rc-5+/6.8.9+/6.6.30+

From: Christian Heusel <christian@heusel.eu>
To: regressions@lists.linux.dev
Cc: "Christian König" <christian.koenig@amd.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	stable@vger.kernel.org,
	"Mario Limonciello" <mario.limonciello@amd.com>,
	heftig@archlinux.org
Subject: [bisected]: Games crash with 6.9rc-5+/6.8.9+/6.6.30+
Date: Wed, 8 May 2024 12:36:24 +0200	[thread overview]
Message-ID: <gifkxwcrswqevdig33inrsieahso2lcxbhcawu6d2qprnujoij@eqg53vwjamts> (raw)

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Hello,

I am reporting this to the regressions mailing list since it has popped
up in the [Arch Linux Bugtracker][0]. It was also [already reported][1]
to the relevant DRM subsystem, but is not tracked here yet.

The issue has been bisected to the following commit by someone on
Gitlab:

    a6ff969fe9cb ("drm/amdgpu: fix visible VRAM handling during faults")

The DRM maintainers have said that this could be something that just
worked by chance in the past:

[Comment 1][2]

> Christian König (@ckoenig)
> Mhm, no idea of hand. But it could be that this is actually an
> intended result.
>
> Previously we didn't correctly checked if the requirements of an
> application regarding CPU accessible VRAM were meet. Now we return an
> error if things potentially won't work instead of crashing later on.
>
> Can you provide the output of 'sudo cat
> /sys/kernel/debug/dri/0/amdgpu_vram_mm' just before running the game?

[Comment 2][3]
> Damian Marcin Szymański (@AngryPenguinPL):
> @superm1 @ckoenig If you can't fix it before stable 6.9 can we get it
> reverted for now?
>
> Christian König (@ckoenig):
> @AngryPenguinPL no, this is an important bug fix which even needs to
> be backported to older kernels.

All in all this seems to be a rather tricky situation (especially
judging if this is actually a regression or not), so maybe getting some
input from the stable or regression team on how to handle this well
would be good!

(I'll add that I can give no direct input on the issue itself, see this
as a forward / cc type of Email.)

Cheers,
Chris

[0]: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/47
[1]: https://gitlab.freedesktop.org/drm/amd/-/issues/3343
[2]: https://gitlab.freedesktop.org/drm/amd/-/issues/3343#note_2389471
[3]: https://gitlab.freedesktop.org/drm/amd/-/issues/3343#note_2400933

#regzbot introduced: a6ff969fe9cb
#regzbot link: https://gitlab.freedesktop.org/drm/amd/-/issues/3343
#regzbot title: drm/amdgpu: Games crash if above 4g decoding/resize bar is disabled or not supported

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