On Thu, Jun 02, 2022 at 12:38:48PM +0300, Jani Nikula wrote:
> On Wed, 01 Jun 2022, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> >
> > We're not parsing the 5.4 Gbps value for the old eDP fast link
> > training link rate, nor are we parsing the new fast link training
> > link rate field. Remedy both.
> >
> > Note that we're not even using this information for anything
> > currently, so should perhaps just nuke it all unless someone
> > is planning on implementing fast link training finally...
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_bios.c | 32 ++++++++++++-------
> > drivers/gpu/drm/i915/display/intel_vbt_defs.h | 1 +
> > 2 files changed, 21 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> > index c42b9e7d0dce..d701854dc429 100644
> > --- a/drivers/gpu/drm/i915/display/intel_bios.c
> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> > @@ -1367,18 +1367,26 @@ parse_edp(struct drm_i915_private *i915,
> >
> > panel->vbt.edp.pps = *edp_pps;
> >
> > - switch (edp_link_params->rate) {
> > - case EDP_RATE_1_62:
> > - panel->vbt.edp.rate = DP_LINK_BW_1_62;
> > - break;
> > - case EDP_RATE_2_7:
> > - panel->vbt.edp.rate = DP_LINK_BW_2_7;
> > - break;
> > - default:
> > - drm_dbg_kms(&i915->drm,
> > - "VBT has unknown eDP link rate value %u\n",
> > - edp_link_params->rate);
> > - break;
> > + if (i915->vbt.version >= 224) {
> > + panel->vbt.edp.rate =
> > + edp->edp_fast_link_training_rate[panel_type] * 2;
>
> So this is in units of 200 kHz.
Right. Or even more specifically it's 200 kbps units (based on the example
values in the spec). So we'll want *20 here to get the 10 kbps units we
use.
>
> > + } else {
> > + switch (edp_link_params->rate) {
> > + case EDP_RATE_1_62:
> > + panel->vbt.edp.rate = DP_LINK_BW_1_62;
>
> However the DP_LINK_BW_* stuff are the values to be written to DPCD. So
> different things end up in panel->vbt.edp.rate depending on VBT
> version. It's a mess. Should probably have the rate there and throw out
> the DP_LINK_BW_* macros.
Oh right, I forgot those are the DPCD values. I'll switch to real
numbers here.
>
> Otherwise, the logic seems fine.
>
> BR,
> Jani.
>
> > + break;
> > + case EDP_RATE_2_7:
> > + panel->vbt.edp.rate = DP_LINK_BW_2_7;
> > + break;
> > + case EDP_RATE_5_4:
> > + panel->vbt.edp.rate = DP_LINK_BW_5_4;
> > + break;
> > + default:
> > + drm_dbg_kms(&i915->drm,
> > + "VBT has unknown eDP link rate value %u\n",
> > + edp_link_params->rate);
> > + break;
> > + }
> > }
> >
> > switch (edp_link_params->lanes) {
> > diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> > index 14f1e1cc92c5..58aee0a040cf 100644
> > --- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> > +++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> > @@ -638,6 +638,7 @@ struct bdb_sdvo_panel_dtds {
> > #define EDP_30BPP 2
> > #define EDP_RATE_1_62 0
> > #define EDP_RATE_2_7 1
> > +#define EDP_RATE_5_4 2
> > #define EDP_LANE_1 0
> > #define EDP_LANE_2 1
> > #define EDP_LANE_4 3
>
> --
> Jani Nikula, Intel Open Source Graphics Center
--
Ville Syrjälä
Intel
