On 8/28/26 14:19, Viktor Jägersküpper wrote: > 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). >> >> [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
Ahh, yeah, many thx, I had see this downgrade to drm_warn() (which made it to -rc1, yeah \o/), but had not made the right connections. :-/ FWIW, even with that done there is now one amdgpu regression report about this already post-rc1: https://lore.kernel.org/all/CANkdJ2VvJQSBzyOq=LgSW1=z8-yin_r9py2ij0ujdo55+db...@mail.gmail.com/ """ [...] After updating from kernel v7.2.2 to v7.3-rc1, several DRM plane warnings regarding unset blend modes for pixel formats with alpha channels started appearing in dmesg during initialization. [drm] [PLANE:44:plane-0] pixel format with alpha exposed but blend mode not setup. Please fix. [...] """ Will reply there now. Wondering if we need to do something about that if more reports like that show up, but let's wait if that's the case. Ciao, Thorsten
