Re: [PATCH v2 6/8] drm/i915/dp: add 128b/132b support to link status checks

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Jani Nikula <jani.nikula@intel.com>
Cc: intel-gfx@lists.freedesktop.org, uma.shankar@intel.com,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 6/8] drm/i915/dp: add 128b/132b support to link status checks
Date: Wed, 9 Feb 2022 11:17:30 +0200	[thread overview]
Message-ID: <YgOGqmEigGnYIK8f@intel.com> (raw)
In-Reply-To: <87sfsspfsa.fsf@intel.com>

On Wed, Feb 09, 2022 at 11:09:41AM +0200, Jani Nikula wrote:
> On Tue, 08 Feb 2022, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> > On Thu, Feb 03, 2022 at 11:03:55AM +0200, Jani Nikula wrote:
> >> Abstract link status check to a function that takes 128b/132b and 8b/10b
> >> into account, and use it. Also dump link status on failures.
> >> 
> >> Cc: Uma Shankar <uma.shankar@intel.com>
> >> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/display/intel_dp.c       | 39 ++++++++++++++-----
> >>  .../drm/i915/display/intel_dp_link_training.c |  2 +-
> >>  .../drm/i915/display/intel_dp_link_training.h |  4 ++
> >>  3 files changed, 34 insertions(+), 11 deletions(-)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> >> index 146b83916005..8c5590f0409a 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> >> @@ -3628,6 +3628,32 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp)
> >>  			    "Could not write test response to sink\n");
> >>  }
> >>  
> >> +static bool intel_dp_link_ok(struct intel_dp *intel_dp,
> >> +			     u8 link_status[DP_LINK_STATUS_SIZE])
> >> +{
> >> +	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
> >> +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> >> +	bool uhbr = intel_dp->link_rate >= 1000000;
> >> +	bool ok;
> >> +
> >> +	if (uhbr)
> >> +		ok = drm_dp_128b132b_lane_channel_eq_done(link_status,
> >> +							  intel_dp->lane_count);
> >
> > I was pondering whether we need to check more of the bits here. I guess
> > time will tell.
> >
> > Remainder of the series is
> > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Just to be on the safe side, does this cover patches 2 and 4 too?

Yeah, pretty sure I read through all of them.

> 
> And thanks for all the reviews so far, much appreciated!
>
> BR,
> Jani.
> 
> 
> >
> >> +	else
> >> +		ok = drm_dp_channel_eq_ok(link_status, intel_dp->lane_count);
> >> +
> >> +	if (ok)
> >> +		return true;
> >> +
> >> +	intel_dp_dump_link_status(intel_dp, DP_PHY_DPRX, link_status);
> >> +	drm_dbg_kms(&i915->drm,
> >> +		    "[ENCODER:%d:%s] %s link not ok, retraining\n",
> >> +		    encoder->base.base.id, encoder->base.name,
> >> +		    uhbr ? "128b/132b" : "8b/10b");
> >> +
> >> +	return false;
> >> +}
> >> +
> >>  static void
> >>  intel_dp_mst_hpd_irq(struct intel_dp *intel_dp, u8 *esi, u8 *ack)
> >>  {
> >> @@ -3658,14 +3684,7 @@ static bool intel_dp_mst_link_status(struct intel_dp *intel_dp)
> >>  		return false;
> >>  	}
> >>  
> >> -	if (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count)) {
> >> -		drm_dbg_kms(&i915->drm,
> >> -			    "[ENCODER:%d:%s] channel EQ not ok, retraining\n",
> >> -			    encoder->base.base.id, encoder->base.name);
> >> -		return false;
> >> -	}
> >> -
> >> -	return true;
> >> +	return intel_dp_link_ok(intel_dp, link_status);
> >>  }
> >>  
> >>  /**
> >> @@ -3779,8 +3798,8 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
> >>  					intel_dp->lane_count))
> >>  		return false;
> >>  
> >> -	/* Retrain if Channel EQ or CR not ok */
> >> -	return !drm_dp_channel_eq_ok(link_status, intel_dp->lane_count);
> >> +	/* Retrain if link not ok */
> >> +	return !intel_dp_link_ok(intel_dp, link_status);
> >>  }
> >>  
> >>  static bool intel_dp_has_connector(struct intel_dp *intel_dp,
> >> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> >> index cc2b82d9114c..0686da36c428 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> >> @@ -712,7 +712,7 @@ static bool intel_dp_adjust_request_changed(const struct intel_crtc_state *crtc_
> >>  	return false;
> >>  }
> >>  
> >> -static void
> >> +void
> >>  intel_dp_dump_link_status(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
> >>  			  const u8 link_status[DP_LINK_STATUS_SIZE])
> >>  {
> >> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.h b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> >> index dbfb15705aaa..dc1556b46b85 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> >> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> >> @@ -29,6 +29,10 @@ void intel_dp_start_link_train(struct intel_dp *intel_dp,
> >>  void intel_dp_stop_link_train(struct intel_dp *intel_dp,
> >>  			      const struct intel_crtc_state *crtc_state);
> >>  
> >> +void
> >> +intel_dp_dump_link_status(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
> >> +			  const u8 link_status[DP_LINK_STATUS_SIZE]);
> >> +
> >>  /* Get the TPSx symbol type of the value programmed to DP_TRAINING_PATTERN_SET */
> >>  static inline u8 intel_dp_training_pattern_symbol(u8 pattern)
> >>  {
> >> -- 
> >> 2.30.2
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

-- 
Ville Syrjälä
Intel