On Wed, Aug 26, 2026 at 02:28:15AM +0500, Mikhail Gavrilov wrote: > Hi, > > this is not a linux-next-only issue any more: 860e748bddcc came in with the > drm-next pull of the 7.3 merge window, so it now warns on plain mainline. Here > it fires 16 times on every boot - 8 per GPU, on the 4 primary and 4 cursor > planes of each of the two cards in this machine: > > [PLANE:44:plane-0] pixel format with alpha exposed but blend mode not setup > WARNING: drivers/gpu/drm/drm_mode_config.c:872 at > drm_mode_config_validate+0xa16/0x13b0 > > I ran into it on 7.2.0-2709dd5ae32f, bisected it to 860e748bddcc and confirmed > by reverting that commit, before I found this thread. Hardware: > 0000:03:00.0 Navi 31 (DCN 3.2) and 0000:0f:00.0 Raphael iGPU (DCN 3.1.5). > > Nobody has put this on regzbot yet, so: > > #regzbot introduced: 860e748bddcc > #regzbot title: drm: WARNING at drm_mode_config_validate() for planes > exposing alpha without a blend mode property > #regzbot monitor: > https://lore.kernel.org/all/[email protected]/ > > Status as far as I can see it: Melissa Wen's v3 series (monitored above) fixes > amdgpu for both DCN and DCE, has Reviewed-by from Alex Hung and Tested-by from > Daniel Wheeler, and I tested it here too - the warnings are gone on both GPUs. > It is in neither linux-next nor amd-staging-drm-next so far. 271e90eb5f9f > ("drm: use drm_warn() in validate_blend_mode_for_alpha_formats()") turns the > splat into a plain warning and went to drm-next on 2026-08-20 as part of > drm-misc-next-fixes-2026-08-20, but has not reached mainline either. Other > drivers are being fixed in separate threads (imx dcss, rockchip, vkms). > > Since this was introduced during the 7.3 merge window, the fixes should land > in 7.3 rather than wait for the next one.
I can confirm this regression. It's hitting me here too on Linus's latest tree. 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... thanks, greg k-h
