6.10/bisected/regression - commits bc87d666c05 and 6d4279cb99ac cause appearing green flashing bar on top of screen on Radeon 6900XT and 120Hz

[Mikhail Gavrilov]

Hi,
Day before yesterday I replaced 7900XTX to 6900XT for got clear in
which kernel first time appeared warning message "DMA-API: amdgpu
0000:0f:00.0: cacheline tracking EEXIST, overlapping mappings aren't
supported".
The kernel 6.3 and older won't boot on a computer with Radeon 7900XTX.
When I booted the system with 6900XT I saw a green flashing bar on top
of the screen when I typed commands in the gnome terminal which was
maximized on full screen.
Demonstration: https://youtu.be/tTvwQ_5pRkk
For reproduction you need Radeon 6900XT GPU connected to 120Hz OLED TV by HDMI.

I bisected the issue and the first commit which I found was 6d4279cb99ac.
commit 6d4279cb99ac4f51d10409501d29969f687ac8dc (HEAD)
Author: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
Date:   Tue Mar 26 10:42:05 2024 -0600

    drm/amd/display: Drop legacy code

    This commit removes code that are not used by display anymore.

    Acked-by: Hamza Mahfooz <hamza.mahfooz at amd.com>
    Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
    Signed-off-by: Alex Deucher <alexander.deucher at amd.com>

 drivers/gpu/drm/amd/display/dc/inc/hw/stream_encoder.h         |  4 ----
 drivers/gpu/drm/amd/display/dc/inc/resource.h                  |  7 -------
 drivers/gpu/drm/amd/display/dc/optc/dcn20/dcn20_optc.c         | 10 ----------
 drivers/gpu/drm/amd/display/dc/resource/dcn21/dcn21_resource.c | 33
+--------------------------------
 4 files changed, 1 insertion(+), 53 deletions(-)

Every time after bisecting I usually make sure that I found the right
commit and build the kernel with revert of the bad commit.
But this time I again observed an issue after running a kernel builded
without commit 6d4279cb99ac.
And I decided to find a second bad commit.
The second bad commit has been bc87d666c05.
commit bc87d666c05a13e6d4ae1ddce41fc43d2567b9a2 (HEAD)
Author: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
Date:   Tue Mar 26 11:55:19 2024 -0600

    drm/amd/display: Add fallback configuration for set DRR in DCN10

    Set OTG/OPTC parameters to 0 if something goes wrong on DCN10.

    Acked-by: Hamza Mahfooz <hamza.mahfooz at amd.com>
    Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
    Signed-off-by: Alex Deucher <alexander.deucher at amd.com>

 drivers/gpu/drm/amd/display/dc/optc/dcn10/dcn10_optc.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

After reverting both these commits on top of 54f71b0369c9 the issue is gone.

I also attach the build config.

My hardware specs: https://linux-hardware.org/?probe=f25a873c5e

Rodrigo or anyone else from the AMD team can you look please.

-- 
Best Regards,
Mike Gavrilov.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: .config.zip
Type: application/zip
Size: 66526 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20240526/9cdbf82d/attachment-0001.zip>