On 8/28/26 09:22, Thorsten Leemhuis wrote:
> On 8/27/26 19:14, Melissa Wen wrote:
>> On 27/08/2026 18:37, Melissa Wen wrote:
>>> On 27/08/2026 15:34, Alex Deucher wrote:
>>>> On Wed, Aug 26, 2026 at 7:20 AM Melissa Wen <[email protected]> wrote:
>>>>> PREMULTI was the default DRM blend mode until 9813e158d13d
>>>>> ("drm/drm_blend: allow blend mode property without PREMULTI")
>>>>> introduced
>>>>> the possibility of exposing the blend mode property without PREMULTI
>>>>> being supported. However, __drm_atomic_helper_plane_state_init() still
>>>>> resets pixel_blend_mode to PREMULTI (hardcoded), ignoring the supported
>>>>> mode in this property. In the same series, 860e748bddcc ("drm: ensure
>>>>> blend mode supported if pixel format with alpha exposed") starts
>>>>> warning
>>>>> drivers that supports alpha formats in a given planes but doesn't
>>>>> support blend mode property, which includes AMD primary and cursor
>>>>> planes.
>> [...]
>>>> I presume you are planning to apply this directly to drm-misc for 7.3?
>>>
>>> Right, I'll apply to drm-misc-fixes, just doing it now.
>>
>> Or not now. I have to wait for -rc1.
>> I'll keep it on my radar.
> Hmmm, that sounds like these fixes will miss -rc1. But wouldn't it be
> good to get them included there, as they afaik (please correct me if I'm
> wrong, is easy to mix something up from the outside!) the warnings that
> Greg described as ""It's not good to boot and have a bunch of warnings
> already happening, resulting in a "tainted" kernel before I have the
> chance to break anything manually myself...""[1], as more people then
> will likely encounter this (and then waste time on bisecting an issue
> known for weeks for which a fix exists).
> 
> Ciao, Thorsten
> 
> [1]
> https://lore.kernel.org/all/2026082651-spinning-cornbread-33ba@gregkh/

If I understand correctly, the *actual* fix (for all affected drivers)
will make it into 7.3-rc1, see this answer to my question:
https://lore.kernel.org/dri-devel/20260826-brave-nyala-of-elevation-d23aea@houat/

This fix is queued in drm-next:
https://gitlab.freedesktop.org/drm/kernel/-/commit/271e90eb5f9ff34951647e5ed33c1775eebcca50

It seems the drm-next branch is used for fixes arriving during the
merge window, which might be confusing for outsiders.

I hope that clears up the confusion.

Viktor

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