Re: AMDGPU - Regression: Black screen due to commit 16dc8bc27c2aa3c93905d3e885e27f1e3535f09a

[Mario Limonciello]

On 6/21/25 10:18 AM, Walt Holman wrote:
> Hello,
>
> With the latest drm fixes this week on 6.16-rc2, I am experiencing a
> black screen instead of the sddm greeter and the GPU appears to be
> locked up. I can ssh into the laptop and reboot it, but that's about
> it. I have bisected the commit to commit id:
> 16dc8bc27c2aa3c93905d3e885e27f1e3535f09a and upon reverting the
> commit, the system works as normal. The hardware is an Asus Rog
> Zephyrus G16 with AMD Ryzen AI 9 HX 370 w/ Radeon 890M video. I'm able
> to test patches etc.. if need be.

Hi there,

By chance do you have an OLED panel?  If so can you please try the patch 
attached to this bug?

https://gitlab.freedesktop.org/drm/amd/-/issues/4338

Thanks,

> 16dc8bc27c2aa3c93905d3e885e27f1e3535f09a is the first bad commit
> commit 16dc8bc27c2aa3c93905d3e885e27f1e3535f09a (HEAD)
> Author: Mario Limonciello <mario.limonciello@xxxxxxx>
> Date:   Thu May 29 09:46:32 2025 -0500
>
>      drm/amd/display: Export full brightness range to userspace
>
>      [WHY]
>      Userspace currently is offered a range from 0-0xFF but the PWM is
>      programmed from 0-0xFFFF.  This can be limiting to some software
>      that wants to apply greater granularity.
>
>      [HOW]
>      Convert internally to firmware values only when mapping custom
>      brightness curves because these are in 0-0xFF range. Advertise full
>      PWM range to userspace.
>
>      Cc: Mario Limonciello <mario.limonciello@xxxxxxx>
>      Cc: Alex Deucher <alexander.deucher@xxxxxxx>
>      Reviewed-by: Roman Li <roman.li@xxxxxxx>
>      Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
>      Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
>      Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
>      Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
>      (cherry picked from commit 8dbd72cb790058ce52279af38a43c2b302fdd3e5)
>      Cc: stable@xxxxxxxxxxxxxxx
>
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 41
> +++++++++++++++++++++++++++--------------
>   1 file changed, 27 insertions(+), 14 deletions(-)