6.11/regression/bisected - after commit 1b04dcca4fb1, launching some RenPy games causes computer hang

[Mikhail Gavrilov]

On Mon, Aug 5, 2024 at 11:05 PM Mikhail Gavrilov
<mikhail.v.gavrilov at gmail.com> wrote:
>
> Hi,
> After commit 1b04dcca4fb1, launching some RenPy games causes computer hang.
> After the hang, even Alt + sysrq + REISUB can't reboot the computer!
> And no trace in the kernel log!
> For demonstration, I'm going to use the game "Find the Orange Narwhal"
> because it is free and has 100% reproducivity for this issue.
> You can find it in the Steam Store:
> https://store.steampowered.com/app/2946010/Find_the_Orange_Narwhal/
> I uploaded demonstration video to youtube: https://youtu.be/yVW6rImRpXw
>
> Unfortunately, I can't check the revert commit 1541d63c5fe2 because of
> conflicts.
>
> mikhail at primary-ws ~/p/g/linux (master)> git reset v6.11-rc1 --hard
> HEAD is now at 8400291e289e Linux 6.11-rc1
>
> mikhail at primary-ws ~/p/g/linux (master)> git revert -n 1b04dcca4fb1
> Auto-merging drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> CONFLICT (content): Merge conflict in
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> Auto-merging drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> Auto-merging drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> Auto-merging drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> CONFLICT (content): Merge conflict in
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> error: could not revert 1b04dcca4fb1... drm/amd/display: Introduce
> overlay cursor mode
> hint: after resolving the conflicts, mark the corrected paths
> hint: with 'git add <paths>' or 'git rm <paths>'
> hint: Disable this message with "git config advice.mergeConflict false"
>
> commit 1b04dcca4fb10dd3834893a60de74edd99f2bfaf
> Author: Leo Li <sunpeng.li at amd.com>
> Date:   Thu Jan 18 16:29:49 2024 -0500
>
>     drm/amd/display: Introduce overlay cursor mode
>
>     [Why]
>
>     DCN is the display hardware for amdgpu. DRM planes are backed by DCN
>     hardware pipes, which carry pixel data from one end (memory), to the
>     other (output encoder).
>
>     Each DCN pipe has the ability to blend in a cursor early on in the
>     pipeline. In other words, there are no dedicated cursor planes in DCN,
>     which makes cursor behavior somewhat unintuitive for compositors.
>
>     For example, if the cursor is in RGB format, but the top-most DRM plane
>     is in YUV format, DCN will not be able to blend them. Because of this,
>     amdgpu_dm rejects all configurations where a cursor needs to be enabled
>     on top of a YUV formatted plane.
>
>     From a compositor's perspective, when computing an allocation for
>     hardware plane offloading, this cursor-on-yuv configuration result in an
>     atomic test failure. Since the failure reason is not obvious at all,
>     compositors will likely fall back to full rendering, which is not ideal.
>
>     Instead, amdgpu_dm can try to accommodate the cursor-on-yuv
>     configuration by opportunistically reserving a separate DCN pipe just
>     for the cursor. We can refer to this as "overlay cursor mode". It is
>     contrasted with "native cursor mode", where the native DCN per-pipe
>     cursor is used.
>
>     [How]
>
>     On each crtc, compute whether the cursor plane should be enabled in
>     overlay mode. If it is, mark the CRTC as requesting overlay cursor mode.
>
>     Overlay cursor should be enabled whenever there exists a underlying
>     plane that has YUV format, or is scaled differently than the cursor. It
>     should also be enabled if there is no underlying plane, or if underlying
>     planes do not cover the entire CRTC.
>
>     During DC validation, attempt to enable a separate DCN pipe for the
>     cursor if it's in overlay mode. If that fails, or if no overlay mode is
>     requested, then fallback to native mode.
>
>     v2:
>     * Update commit message for when overlay cursor should be enabled
>     * Also consider scale and no-underlying-plane case (cursor on crtc bg)
>     * Consider all underlying planes when determinig overlay/native, not
>       just the plane immediately beneath the cursor, as it may not cover the
>       entire CRTC.
>     * Fix typo s/decending/descending/
>     * Force native cursor on pre-DCN hardware
>
>     Reviewed-by: Harry Wentland <harry.wentland at amd.com>
>     Acked-by: Zaeem Mohamed <zaeem.mohamed at amd.com>
>     Signed-off-by: Leo Li <sunpeng.li at amd.com>
>     Acked-by: Harry Wentland <harry.wentland at amd.com>
>     Acked-by: Pekka Paalanen <pekka.paalanen at collabora.com>
>     Tested-by: Daniel Wheeler <daniel.wheeler at amd.com>
>     Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c       | 490
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------------------------
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h       |   7 +++
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c  |   1 +
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c |  13 ++++-
>  4 files changed, 389 insertions(+), 122 deletions(-)
>
>
> My hardware specs are: https://linux-hardware.org/?probe=61bd7390a9
>
> Leo, can you look into it, please?
>

Hi,
Is anyone trying to look into it?
I continue to reproduce this issue on fresh kernel builds 6.11-rc4+.
In addition to the RenPy engine, the problem also reproduces on games
from Ubisoft, such as Far Cry 4.
A very important note that I missed in the first message.
To reproduce the problem, you need to enable scaling in Gnome for
HiDPI monitors.
I am using 4K resolution with 200% of fractional scaling.

-- 
Best Regards,
Mike Gavrilov.