Re: [PATCH] drm/i915: Reject async flips with bigjoiner

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Dec 13, 2023 at 08:36:49PM +0200, Lisovskiy, Stanislav wrote:
> On Mon, Dec 11, 2023 at 10:11:34AM +0200, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Currently async flips are busted when bigjoiner is in use.
> > As a short term fix simply reject async flips in that case.
> > 
> > Cc: stable@vger.kernel.org
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9769
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > index d955957b7d18..61053c19f4cc 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -5926,6 +5926,17 @@ static int intel_async_flip_check_uapi(struct intel_atomic_state *state,
> >  		return -EINVAL;
> >  	}
> >  
> > +	/*
> > +	 * FIXME: Bigjoiner+async flip is busted currently.
> > +	 * Remove this check once the issues are fixed.
> > +	 */
> > +	if (new_crtc_state->bigjoiner_pipes) {
> > +		drm_dbg_kms(&i915->drm,
> > +			    "[CRTC:%d:%s] async flip disallowed with bigjoiner\n",
> > +			    crtc->base.base.id, crtc->base.name);
> > +		return -EINVAL;
> > +	}
> > +
> 
> Was recently wondering, whether should we add some kind of helper
> func for that check to look more readable, i.e instead of just
> checking if crtc_state->bigjoiner_pipes != 0, call smth like
> is_bigjoiner_used(new_crtc_state)..

I suppose we could have something like that. We do have something
along those lines for eg. port sync. The difference being that
port sync has a bit more state than a single bitmask, so it's
more useful there.

> 
> Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
>

Thanks.

> >  	for_each_oldnew_intel_plane_in_state(state, plane, old_plane_state,
> >  					     new_plane_state, i) {
> >  		if (plane->pipe != crtc->pipe)
> > -- 
> > 2.41.0
> > 

-- 
Ville Syrjälä
Intel