[Intel-gfx] [PATCH] drm/i915/display: Fix the dsc check while selecting min_cdclk

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Jani Nikula
> Sent: Monday, September 27, 2021 3:09 PM
> To: Kulkarni, Vandita <vandita.kulkarni at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Kulkarni, Vandita <vandita.kulkarni at intel.com>
> Subject: Re: [Intel-gfx] [PATCH] drm/i915/display: Fix the dsc check while selecting
> min_cdclk
> 
> On Wed, 15 Sep 2021, Vandita Kulkarni <vandita.kulkarni at intel.com> wrote:
> > The right parameter that selects second dsc engine is dsc_split.
> > Hence use dsc_split instead of slice_count while selecting the cdclk
> > in order to accommodate 1ppc limitaion of vdsc.
> >
> > Fixes: fe01883fdcef ("drm/i915: Get proper min cdclk if vDSC enabled")
> > Suggested-by: Jani Nikula <jani.nikula at intel.com>
> > Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
> 
> Sorry for the delay!
> 
> Reviewed-by: Jani Nikula <jani.nikula at intel.com>

Pushed the change to drm-intel-next. Thanks for the patch and review.

Regards,
Uma Shankar
> > ---
> >  drivers/gpu/drm/i915/display/intel_cdclk.c | 10 ++++------
> >  1 file changed, 4 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > index 9aec17b33819..3a1cdb3937aa 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > @@ -2140,13 +2140,11 @@ int intel_crtc_compute_min_cdclk(const struct
> intel_crtc_state *crtc_state)
> >  	min_cdclk = max(intel_planes_min_cdclk(crtc_state), min_cdclk);
> >
> >  	/*
> > -	 * VDSC engine can process only 1 pixel per Cd clock.
> > -	 * In case VDSC is used and max slice count == 1,
> > -	 * max supported pixel clock should be 100% of CD clock.
> > -	 * Then do min_cdclk and pixel clock comparison to get cdclk.
> > +	 * When we decide to use only one VDSC engine, since
> > +	 * each VDSC operates with 1 ppc throughput, pixel clock
> > +	 * cannot be higher than the VDSC clock (cdclk)
> >  	 */
> > -	if (crtc_state->dsc.compression_enable &&
> > -	    crtc_state->dsc.slice_count == 1)
> > +	if (crtc_state->dsc.compression_enable &&
> > +!crtc_state->dsc.dsc_split)
> >  		min_cdclk = max(min_cdclk, (int)crtc_state->pixel_rate);
> >
> >  	/*
> 
> --
> Jani Nikula, Intel Open Source Graphics Center