Re: [PATCH 1/5] drm/i915/dp: Add helper to check DSC1.2 for HDMI2.1 DFP

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

On 8/23/2022 4:32 PM, Jani Nikula wrote:
> On Mon, 22 Aug 2022, Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> wrote:
> > Add helper function to check if Downstream HDMI 2.1 sink supports
> > DSC1.2.
> If we do this, are we going to add helpers for all the details in
> display_info, when there's no conversions being done? I think the answer
> should be "no".
>
> i.e. why do we really need this?

Hmm well initially I was checking both the dsc_max_frl rate and dsc 
version, but dropped the dsc_max_frl rate check later.

(need another patch series to fix DSC parsing from HFVSDB: 
https://patchwork.freedesktop.org/series/107146/ )

In current form, this function does seem unnecessary,  I will drop this 
patch from the series.

Thanks & Regards,

Ankit


> BR,
> Jani.
>
> > Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/display/intel_dp.c | 13 +++++++++++--
> >   1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 32292c0be2bd..fdf82373a22d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -118,6 +118,15 @@ bool intel_dp_is_edp(struct intel_dp *intel_dp)
> >   static void intel_dp_unset_edid(struct intel_dp *intel_dp);
> >   static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc);
> >   
> > +static bool
> > +is_dfp_hdmi_sink_dsc_1_2(struct intel_dp *intel_dp)
> > +{
> > +	struct intel_connector *intel_connector = intel_dp->attached_connector;
> > +	struct drm_connector *connector = &intel_connector->base;
> > +
> > +	return connector->display_info.hdmi.dsc_cap.v_1p2;
> > +}
> > +
> >   /* Is link rate UHBR and thus 128b/132b? */
> >   bool intel_dp_is_uhbr(const struct intel_crtc_state *crtc_state)
> >   {
> > @@ -2393,7 +2402,7 @@ static int intel_dp_hdmi_sink_max_frl(struct intel_dp *intel_dp)
> >   	rate_per_lane = connector->display_info.hdmi.max_frl_rate_per_lane;
> >   	max_frl_rate = max_lanes * rate_per_lane;
> >   
> > -	if (connector->display_info.hdmi.dsc_cap.v_1p2) {
> > +	if (is_dfp_hdmi_sink_dsc_1_2(intel_dp)) {
> >   		max_dsc_lanes = connector->display_info.hdmi.dsc_cap.max_lanes;
> >   		dsc_rate_per_lane = connector->display_info.hdmi.dsc_cap.max_frl_rate_per_lane;
> >   		if (max_dsc_lanes && dsc_rate_per_lane)
> > @@ -2605,7 +2614,7 @@ intel_dp_pcon_dsc_configure(struct intel_dp *intel_dp,
> >   	if (!intel_connector)
> >   		return;
> >   	connector = &intel_connector->base;
> > -	hdmi_is_dsc_1_2 = connector->display_info.hdmi.dsc_cap.v_1p2;
> > +	hdmi_is_dsc_1_2 = is_dfp_hdmi_sink_dsc_1_2(intel_dp);
> >   
> >   	if (!drm_dp_pcon_enc_is_dsc_1_2(intel_dp->pcon_dsc_dpcd) ||
> >   	    !hdmi_is_dsc_1_2)