[PATCH] drm/atomic: clarify the rules around drm_atomic_state->allow_modeset

[Simona Vetter]

On Wed, Jan 08, 2025 at 08:34:28PM +0200, Dmitry Baryshkov wrote:
> On Wed, Jan 08, 2025 at 06:24:16PM +0100, Simona Vetter wrote:
> > msm is automagically upgrading normal commits to full modesets, and
> > that's a big no-no:
> > 
> > - for one this results in full on->off->on transitions on all these
> >   crtc, at least if you're using the usual helpers. Which seems to be
> >   the case, and is breaking uapi
> > 
> > - further even if the ctm change itself would not result in flicker,
> >   this can hide modesets for other reasons. Which again breaks the
> >   uapi
> > 
> > v2: I forgot the case of adding unrelated crtc state. Add that case
> > and link to the existing kerneldoc explainers. This has come up in an
> > irc discussion with Manasi and Ville about intel's bigjoiner mode.
> > Also cc everyone involved in the msm irc discussion, more people
> > joined after I sent out v1.
> > 
> > v3: Wording polish from Pekka and Thomas
> > 
> > Acked-by: Pekka Paalanen <pekka.paalanen at collabora.com>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Maxime Ripard <mripard at kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann at suse.de>
> > Cc: David Airlie <airlied at gmail.com>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Pekka Paalanen <pekka.paalanen at collabora.com>
> > Cc: Rob Clark <robdclark at gmail.com>
> > Cc: Simon Ser <contact at emersion.fr>
> > Cc: Manasi Navare <navaremanasi at google.com>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Abhinav Kumar <quic_abhinavk at quicinc.com>
> > Cc: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> > Signed-off-by: Simona Vetter <simona.vetter at intel.com>
> > Signed-off-by: Simona Vetter <simona.vetter at ffwll.ch>
> > ---
> >  include/drm/drm_atomic.h | 23 +++++++++++++++++++++--
> >  1 file changed, 21 insertions(+), 2 deletions(-)
> > 
> 
> Acked-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>

Applied to drm-misc-next, thanks for pinging me about this one.
-Sima
-- 
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch