Re: [PATCH 1/2] drm/amd/display: Fix preferred link rate for NUTMEG

["Timur Kristóf" <timur.kristof@gmail.com>]

On 2026. július 11., szombat 21:35:07 közép-európai nyári idő Lionso Alejandro 
Pacheco Vacacela wrote:
> Hi,
> 
> I independently hit this regression on a desktop Kaveri system and can
> confirm this patch fixes it:
> 
>   - AMD A10-7850K (Kaveri, DCE 8.1), MSI A68HM-E33, VGA monitor on the
>     onboard output (NUTMEG DP-to-VGA bridge)
>   - Debian kernel 7.1.3 (amdgpu.cik_support=1): VGA monitor receives no
>     signal from KMS takeover on; dmesg shows
>     "[drm] enabling link 2 failed: 15" (DC_FAIL_DP_LINK_TRAINING).
>   - Applying just this patch (1/2) on top of v7.1.3 restores VGA output
>     with DC enabled: the link trains, the CRTC comes up at 1360x768@60,
>     and the fix survived three consecutive reboots.
> 
> Tested-by: Lionso Alejandro Pacheco Vacacela <lionso@murena.io>

Thank you for the testing!
I would appreciate if you could verify that the second patch also works well.

> 
> Two notes:
> 
> 1. The Fixes: tag references b74322eea36b, but that hash does not exist
>    in mainline — it looks like an amd-staging-internal id. In Linus'
>    tree the offending commit is:
> 
>      a62346043a89 ("drm/amd/display: Fix coding style issue")
> 
>    It would be good to correct this before the patch is pushed so the
>    stable tooling can resolve the dependency.

As far as I remember the regression hasn't made it upstream yet when I made 
the fix, so the hash didn't exist in Linus's tree yet.

> 
> 2. Since the offending commit shipped in v7.1, could this be annotated
>    Cc: stable@vger.kernel.org # 7.1.x (or nominated for 7.1.y once it
>    lands in mainline)? Every Kaveri/Kabini/Mullins system with a VGA
>    monitor loses display output on release kernels.

Agreed. Alex can you please backport this to 7.1?

Thanks & best regards,
Timur