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

[Mikhail Gavrilov]

On Sun, May 26, 2024 at 7:06 PM Mikhail Gavrilov
<mikhail.v.gavrilov at gmail.com> wrote:
>
> 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.
>

Did anyone watch?

-- 
Best Regards,
Mike Gavrilov.