[PATCH v3 3/3] drm/i915/display: move min_hblank from dp_mst.c to dp.c

[Imre Deak]

On Tue, Apr 22, 2025 at 10:25:48AM +0300, Govindapillai, Vinod wrote:
> [...]
>
> > > +3263,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> > > >  				       &pipe_config->dp_m_n);
> > > >  	}
> > > > 
> > > > +	intel_dp_compute_min_hblank(link_bpp_x16, pipe_config, conn_state,
> > > > +				    pipe_config->dsc.compression_enable);
> > > > +
> > > >  	/* FIXME: abstract this better */
> > > >  	if (pipe_config->splitter.enable)
> > > >  		pipe_config->dp_m_n.data_m *= pipe_config->splitter.link_count;
>
> [...]
>
> > > @@ -301,12 +281,11 @@ int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp,
> > > >  		local_bw_overhead = intel_dp_mst_bw_overhead(crtc_state,
> > > >  							     false, dsc_slice_count, link_bpp_x16);
> > > > 
> > > > -		intel_dp_mst_compute_min_hblank(crtc_state, link_bpp_x16);
> > > > -
> > > >  		intel_dp_mst_compute_m_n(crtc_state,
> > > >  					 local_bw_overhead,
> > > >  					 link_bpp_x16,
> > > >  					 &crtc_state->dp_m_n);
> > > > +		intel_dp_compute_min_hblank(link_bpp_x16, crtc_state, conn_state, dsc);
> > > 
> > > Also I wanted to check if this is the right place to call
> > > intel_dp_compute_min_hblank()? Can't this be called once we settle a link_bpp.
> > > May be from mst_stream_compute_config() before calling
> > > intel_dp_audio_compute_config(). @Imre pls comment.

Yes, it would be better not to recompute the min_hblank value for each bpp.
So just moving intel_dp_compute_min_hblank() before
intel_vrr_compute_config() in mst_stream_compute_config(), similarly how
this is done for the SST case above in intel_dp_compute_config().

> > Here the calculation is done as part of the m and n calculation and
> > this function is called from mst_stream_compute_config and is done
> > before dp_audio_compute_config().  Let me know if any change
> > required will do.

> Why do we need to do this at this point where we iterate through for
> each bpp_x16 "for (bpp_x16 = max_bpp_x16; bpp_x16 >= min_bpp_x16;
> bpp_x16 -= bpp_step_x16) {" as it doesn't influence any decision on in
> this loop! 
> 
> BR
> Vinod