Re: [PATCH 3/4] drm/i915/dp_mst: Use helpers to get dsc min/max input bpc

["Nautiyal, Ankit K" <ankit.k.nautiyal@xxxxxxxxx>]

On 11/27/2023 3:07 PM, Jani Nikula wrote:
> On Mon, 27 Nov 2023, Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> wrote:
> > Use helpers for source min/max input bpc with DSC.
> > While at it, make them return int instead of u8.
> >
> > v2: Make the helpers return int instead of u8. (Jani)
> >
> > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> > Reviewed-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/display/intel_dp.c     |  6 ++----
> >   drivers/gpu/drm/i915/display/intel_dp.h     |  2 ++
> >   drivers/gpu/drm/i915/display/intel_dp_mst.c | 11 ++++-------
> >   3 files changed, 8 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 1f68d4819282..74000b65829e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -1622,8 +1622,7 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> >   	return -EINVAL;
> >   }
> >   
> > -static
> > -u8 intel_dp_dsc_max_src_input_bpc(struct drm_i915_private *i915)
> > +int intel_dp_dsc_max_src_input_bpc(struct drm_i915_private *i915)
> >   {
> >   	if (!HAS_DSC(i915))
> >   		return 0;
> > @@ -2022,8 +2021,7 @@ static int dsc_compute_compressed_bpp(struct intel_dp *intel_dp,
> >   					   dsc_max_bpp, dsc_min_bpp, pipe_bpp, timeslots);
> >   }
> >   
> > -static
> > -u8 intel_dp_dsc_min_src_input_bpc(struct drm_i915_private *i915)
> > +int intel_dp_dsc_min_src_input_bpc(struct drm_i915_private *i915)
> >   {
> >   	/* Min DSC Input BPC for ICL+ is 8 */
> >   	return HAS_DSC(i915) ? 8 : 0;
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> > index 05db46b111f2..f613ced9eda6 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.h
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> > @@ -184,5 +184,7 @@ intel_dp_compute_config_link_bpp_limits(struct intel_dp *intel_dp,
> >   					struct link_config_limits *limits);
> >   
> >   void intel_dp_get_dsc_sink_cap(u8 dpcd_rev, struct intel_connector *connector);
> > +int intel_dp_dsc_max_src_input_bpc(struct drm_i915_private *i915);
> > +int intel_dp_dsc_min_src_input_bpc(struct drm_i915_private *i915);
> >   
> >   #endif /* __INTEL_DP_H__ */
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > index 63364c9602ef..01e9d6fb9548 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> > @@ -293,17 +293,14 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
> >   	int i, num_bpc;
> >   	u8 dsc_bpc[3] = {};
> >   	int min_bpp, max_bpp, sink_min_bpp, sink_max_bpp;
> > -	u8 dsc_max_bpc;
> > +	u8 dsc_max_bpc, dsc_min_bpc;
> >   	int min_compressed_bpp, max_compressed_bpp;
> >   
> > -	/* Max DSC Input BPC for ICL is 10 and for TGL+ is 12 */
> > -	if (DISPLAY_VER(i915) >= 12)
> > -		dsc_max_bpc = min_t(u8, 12, conn_state->max_requested_bpc);
> > -	else
> > -		dsc_max_bpc = min_t(u8, 10, conn_state->max_requested_bpc);
> > +	dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(i915);
> > +	dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
> >   
> >   	max_bpp = min_t(u8, dsc_max_bpc * 3, limits->pipe.max_bpp);
> > -	min_bpp = limits->pipe.min_bpp;
> > +	min_bpp = max_t(u8, dsc_min_bpc * 3, limits->pipe.min_bpp);
> I thought it would be obvious you'd also need to change these to ints
> and drop the forced u8 etc.

Ah ok. But still in some places we need to force to u8 when comparing 
with conn_state->max_requested_bpc,which is u8.

Regards,

Ankit


> BR,
> Jani.
>
> >   
> >   	num_bpc = drm_dp_dsc_sink_supported_input_bpcs(connector->dp.dsc_dpcd,
> >   						       dsc_bpc);