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From: Imre Deak <imre.deak@intel.com>
To: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 02/20] drm/i915/dp: Move link train params to a substruct in intel_dp
Date: Wed, 15 May 2024 16:26:50 +0300	[thread overview]
Message-ID: <ZkS4Gtgfha4hBndA@ideak-desk.fi.intel.com> (raw)
In-Reply-To: <87h6ezck4u.fsf@intel.com>

On Wed, May 15, 2024 at 03:52:33PM +0300, Jani Nikula wrote:
> On Tue, 14 May 2024, Imre Deak <imre.deak@intel.com> wrote:
> > For clarity move the link training parameters updated during link
> > training based on the pass/fail LT result under a substruct in intel_dp.
> > This prepares for later patches in this patchset adding similar params
> > here. Rename intel_dp_reset_max_link_params() to
> > intel_dp_reset_link_train_params() to better reflect what state gets
> > reset.
> 
> High level bikeshedding, why "link_train" instead of just "link"?

It was link training I've been thinking about and that it's important to
know which state gets updated during LT and gets reset after a hotplug.

> You could have three groups: source, sink and link.

Ok, makes sense and link_train could be instead a more generic link
container.

> 
> BR,
> Jani.
> 
> 
> >
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  .../drm/i915/display/intel_display_types.h    | 12 ++++----
> >  drivers/gpu/drm/i915/display/intel_dp.c       | 30 +++++++++----------
> >  2 files changed, 22 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index fec3de25ea54e..7edb533758416 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1738,7 +1738,6 @@ struct intel_dp {
> >  	u8 lane_count;
> >  	u8 sink_count;
> >  	bool link_trained;
> > -	bool reset_link_params;
> >  	bool use_max_params;
> >  	u8 dpcd[DP_RECEIVER_CAP_SIZE];
> >  	u8 psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
> > @@ -1759,10 +1758,13 @@ struct intel_dp {
> >  	/* intersection of source and sink rates */
> >  	int num_common_rates;
> >  	int common_rates[DP_MAX_SUPPORTED_RATES];
> > -	/* Max lane count for the current link */
> > -	int max_link_lane_count;
> > -	/* Max rate for the current link */
> > -	int max_link_rate;
> > +	struct {
> > +		/* Max lane count for the current link */
> > +		int max_lane_count;
> > +		/* Max rate for the current link */
> > +		int max_rate;
> > +	} link_train;
> > +	bool reset_link_params;
> >  	int mso_link_count;
> >  	int mso_pixel_overlap;
> >  	/* sink or branch descriptor */
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 6b8a94d0ca999..ffa627c63e048 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -372,13 +372,13 @@ int intel_dp_max_common_lane_count(struct intel_dp *intel_dp)
> >  
> >  int intel_dp_max_lane_count(struct intel_dp *intel_dp)
> >  {
> > -	switch (intel_dp->max_link_lane_count) {
> > +	switch (intel_dp->link_train.max_lane_count) {
> >  	case 1:
> >  	case 2:
> >  	case 4:
> > -		return intel_dp->max_link_lane_count;
> > +		return intel_dp->link_train.max_lane_count;
> >  	default:
> > -		MISSING_CASE(intel_dp->max_link_lane_count);
> > +		MISSING_CASE(intel_dp->link_train.max_lane_count);
> >  		return 1;
> >  	}
> >  }
> > @@ -644,7 +644,7 @@ static bool intel_dp_link_params_valid(struct intel_dp *intel_dp, int link_rate,
> >  	 * boot-up.
> >  	 */
> >  	if (link_rate == 0 ||
> > -	    link_rate > intel_dp->max_link_rate)
> > +	    link_rate > intel_dp->link_train.max_rate)
> >  		return false;
> >  
> >  	if (lane_count == 0 ||
> > @@ -705,8 +705,8 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
> >  				    "Retrying Link training for eDP with same parameters\n");
> >  			return 0;
> >  		}
> > -		intel_dp->max_link_rate = intel_dp_common_rate(intel_dp, index - 1);
> > -		intel_dp->max_link_lane_count = lane_count;
> > +		intel_dp->link_train.max_rate = intel_dp_common_rate(intel_dp, index - 1);
> > +		intel_dp->link_train.max_lane_count = lane_count;
> >  	} else if (lane_count > 1) {
> >  		if (intel_dp_is_edp(intel_dp) &&
> >  		    !intel_dp_can_link_train_fallback_for_edp(intel_dp,
> > @@ -716,8 +716,8 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
> >  				    "Retrying Link training for eDP with same parameters\n");
> >  			return 0;
> >  		}
> > -		intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
> > -		intel_dp->max_link_lane_count = lane_count >> 1;
> > +		intel_dp->link_train.max_rate = intel_dp_max_common_rate(intel_dp);
> > +		intel_dp->link_train.max_lane_count = lane_count >> 1;
> >  	} else {
> >  		drm_err(&i915->drm, "Link Training Unsuccessful\n");
> >  		return -1;
> > @@ -1382,7 +1382,7 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
> >  {
> >  	int len;
> >  
> > -	len = intel_dp_common_len_rate_limit(intel_dp, intel_dp->max_link_rate);
> > +	len = intel_dp_common_len_rate_limit(intel_dp, intel_dp->link_train.max_rate);
> >  
> >  	return intel_dp_common_rate(intel_dp, len - 1);
> >  }
> > @@ -3017,10 +3017,10 @@ void intel_dp_set_link_params(struct intel_dp *intel_dp,
> >  	intel_dp->lane_count = lane_count;
> >  }
> >  
> > -static void intel_dp_reset_max_link_params(struct intel_dp *intel_dp)
> > +static void intel_dp_reset_link_train_params(struct intel_dp *intel_dp)
> >  {
> > -	intel_dp->max_link_lane_count = intel_dp_max_common_lane_count(intel_dp);
> > -	intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
> > +	intel_dp->link_train.max_lane_count = intel_dp_max_common_lane_count(intel_dp);
> > +	intel_dp->link_train.max_rate = intel_dp_max_common_rate(intel_dp);
> >  }
> >  
> >  /* Enable backlight PWM and backlight PP control. */
> > @@ -3355,7 +3355,7 @@ void intel_dp_sync_state(struct intel_encoder *encoder,
> >  	intel_dp_tunnel_resume(intel_dp, crtc_state, dpcd_updated);
> >  
> >  	if (crtc_state)
> > -		intel_dp_reset_max_link_params(intel_dp);
> > +		intel_dp_reset_link_train_params(intel_dp);
> >  }
> >  
> >  bool intel_dp_initial_fastset_check(struct intel_encoder *encoder,
> > @@ -5888,7 +5888,7 @@ intel_dp_detect(struct drm_connector *connector,
> >  	 * supports link training fallback params.
> >  	 */
> >  	if (intel_dp->reset_link_params || intel_dp->is_mst) {
> > -		intel_dp_reset_max_link_params(intel_dp);
> > +		intel_dp_reset_link_train_params(intel_dp);
> >  		intel_dp->reset_link_params = false;
> >  	}
> >  
> > @@ -6740,7 +6740,7 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
> >  
> >  	intel_dp_set_source_rates(intel_dp);
> >  	intel_dp_set_common_rates(intel_dp);
> > -	intel_dp_reset_max_link_params(intel_dp);
> > +	intel_dp_reset_link_train_params(intel_dp);
> >  
> >  	/* init MST on ports that can support it */
> >  	intel_dp_mst_encoder_init(dig_port,
> 
> -- 
> Jani Nikula, Intel

  reply	other threads:[~2024-05-15 13:26 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-14 19:13 [PATCH 00/20] drm/i915/dp_mst: Enable link training fallback Imre Deak
2024-05-14 19:13 ` [PATCH 01/20] drm/i915/dp_mst: Align TUs to avoid splitting symbols across MTPs Imre Deak
2024-05-14 19:14 ` [PATCH 02/20] drm/i915/dp: Move link train params to a substruct in intel_dp Imre Deak
2024-05-15 12:52   ` Jani Nikula
2024-05-15 13:26     ` Imre Deak [this message]
2024-05-14 19:14 ` [PATCH 03/20] drm/i915/dp: Move link train fallback to intel_dp_link_training.c Imre Deak
2024-05-14 19:14 ` [PATCH 04/20] drm/i915/dp: Sanitize intel_dp_get_link_train_fallback_values() Imre Deak
2024-05-15 13:05   ` Jani Nikula
2024-05-15 13:20     ` Imre Deak
2024-05-14 19:14 ` [PATCH 05/20] drm/i915: Factor out function to modeset commit a set of pipes Imre Deak
2024-05-14 19:14 ` [PATCH 06/20] drm/i915/dp: Use a commit modeset for link retraining MST links Imre Deak
2024-05-14 19:14 ` [PATCH 07/20] drm/i915/dp: Recheck link state after modeset Imre Deak
2024-05-14 20:26   ` [PATCH v2 " Imre Deak
2024-05-14 19:14 ` [PATCH 08/20] drm/i915/dp: Reduce link params only after retrying with unchanged params Imre Deak
2024-05-14 19:14 ` [PATCH 09/20] drm/i915/dp: Remove the modeset retry event's dependece on atomic state Imre Deak
2024-05-14 19:14 ` [PATCH 10/20] drm/i915/dp: Send a link training modeset-retry uevent to all MST connectors Imre Deak
2024-05-14 19:14 ` [PATCH 11/20] drm/i915/dp: Use check link state work in the hotplug handler Imre Deak
2024-05-14 19:14 ` [PATCH 12/20] drm/i915/dp: Use check link state work in the detect handler Imre Deak
2024-05-14 19:14 ` [PATCH 13/20] drm/i915/dp: Use check link state work in the HPD IRQ handler Imre Deak
2024-05-14 19:14 ` [PATCH 14/20] drm/i915/dp: Disable link retraining after the last fallback step Imre Deak
2024-05-14 19:14 ` [PATCH 15/20] drm/i915/dp_mst: Reset intel_dp->link_trained during disabling Imre Deak
2024-05-14 19:14 ` [PATCH 16/20] drm/i915/dp_mst: Enable link training fallback for MST Imre Deak
2024-05-14 19:14 ` [PATCH 17/20] drm/i915/dp: Add debugfs entries to set a target link rate/lane count Imre Deak
2024-05-15 13:09   ` Jani Nikula
2024-05-15 13:23     ` Imre Deak
2024-05-14 19:14 ` [PATCH 18/20] drm/i915/dp: Add debugfs entry to force link training failure Imre Deak
2024-05-14 19:14 ` [PATCH 19/20] drm/i915/dp: Add debugfs entry to force link retrain Imre Deak
2024-05-14 19:14 ` [PATCH 20/20] drm/i915/dp: Add debugfs entry for link training info Imre Deak
2024-05-14 19:39 ` ✗ Fi.CI.CHECKPATCH: warning for drm/i915/dp_mst: Enable link training fallback Patchwork
2024-05-14 19:39 ` ✗ Fi.CI.SPARSE: " Patchwork
2024-05-14 19:47 ` ✗ Fi.CI.BAT: failure " Patchwork
2024-05-14 20:59 ` ✗ Fi.CI.CHECKPATCH: warning for drm/i915/dp_mst: Enable link training fallback (rev2) Patchwork
2024-05-14 20:59 ` ✗ Fi.CI.SPARSE: " Patchwork
2024-05-14 21:06 ` ✓ Fi.CI.BAT: success " Patchwork
2024-05-15  6:57 ` ✗ Fi.CI.IGT: failure " Patchwork

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