diff mbox series

[v2] drm/i915/dp: revert back to max link rate and lane count on eDP

Message ID 20190405075220.9815-1-jani.nikula@intel.com (mailing list archive)
State New, archived
Headers show
Series [v2] drm/i915/dp: revert back to max link rate and lane count on eDP | expand

Commit Message

Jani Nikula April 5, 2019, 7:52 a.m. UTC
Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
and narrow") started to optize the eDP 1.4+ link config, both per spec
and as preparation for display stream compression support.

Sadly, we again face panels that flat out fail with parameters they
claim to support. Revert, and go back to the drawing board.

v2: Actually revert to max params instead of just wide-and-slow.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
 1 file changed, 10 insertions(+), 59 deletions(-)

Comments

Rodrigo Vivi April 5, 2019, 5:23 p.m. UTC | #1
On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
> Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
> and narrow") started to optize the eDP 1.4+ link config, both per spec
> and as preparation for display stream compression support.
> 
> Sadly, we again face panels that flat out fail with parameters they
> claim to support. Revert, and go back to the drawing board.
> 
> v2: Actually revert to max params instead of just wide-and-slow.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
> Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Manasi Navare <manasi.d.navare@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Matt Atwood <matthew.s.atwood@intel.com>
> Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
> Cc: Dave Airlie <airlied@gmail.com>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v5.0+
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

I can hear from here your "I told you so"... Sorry!

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> ---
>  drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
>  1 file changed, 10 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 72c490..dfa770 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
>  	return -EINVAL;
>  }
>  
> -/* Optimize link config in order: max bpp, min lanes, min clock */
> -static int
> -intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> -				  struct intel_crtc_state *pipe_config,
> -				  const struct link_config_limits *limits)
> -{
> -	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> -	int bpp, clock, lane_count;
> -	int mode_rate, link_clock, link_avail;
> -
> -	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
> -		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> -						   bpp);
> -
> -		for (lane_count = limits->min_lane_count;
> -		     lane_count <= limits->max_lane_count;
> -		     lane_count <<= 1) {
> -			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
> -				link_clock = intel_dp->common_rates[clock];
> -				link_avail = intel_dp_max_data_rate(link_clock,
> -								    lane_count);
> -
> -				if (mode_rate <= link_avail) {
> -					pipe_config->lane_count = lane_count;
> -					pipe_config->pipe_bpp = bpp;
> -					pipe_config->port_clock = link_clock;
> -
> -					return 0;
> -				}
> -			}
> -		}
> -	}
> -
> -	return -EINVAL;
> -}
> -
>  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
>  {
>  	int i, num_bpc;
> @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  	limits.min_bpp = 6 * 3;
>  	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
>  
> -	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> +	if (intel_dp_is_edp(intel_dp)) {
>  		/*
>  		 * Use the maximum clock and number of lanes the eDP panel
> -		 * advertizes being capable of. The eDP 1.3 and earlier panels
> -		 * are generally designed to support only a single clock and
> -		 * lane configuration, and typically these values correspond to
> -		 * the native resolution of the panel. With eDP 1.4 rate select
> -		 * and DSC, this is decreasingly the case, and we need to be
> -		 * able to select less than maximum link config.
> +		 * advertizes being capable of. The panels are generally
> +		 * designed to support only a single clock and lane
> +		 * configuration, and typically these values correspond to the
> +		 * native resolution of the panel.
>  		 */
>  		limits.min_lane_count = limits.max_lane_count;
>  		limits.min_clock = limits.max_clock;
> @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  		      intel_dp->common_rates[limits.max_clock],
>  		      limits.max_bpp, adjusted_mode->crtc_clock);
>  
> -	if (intel_dp_is_edp(intel_dp))
> -		/*
> -		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> -		 * section A.1: "It is recommended that the minimum number of
> -		 * lanes be used, using the minimum link rate allowed for that
> -		 * lane configuration."
> -		 *
> -		 * Note that we use the max clock and lane count for eDP 1.3 and
> -		 * earlier, and fast vs. wide is irrelevant.
> -		 */
> -		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> -							&limits);
> -	else
> -		/* Optimize for slow and wide. */
> -		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> -							&limits);
> +	/*
> +	 * Optimize for slow and wide. This is the place to add alternative
> +	 * optimization policy.
> +	 */
> +	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
>  
>  	/* enable compression if the mode doesn't fit available BW */
>  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> -- 
> 2.20.1
>
Navare, Manasi April 5, 2019, 6:18 p.m. UTC | #2
On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
> Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
> and narrow") started to optize the eDP 1.4+ link config, both per spec
> and as preparation for display stream compression support.
> 
> Sadly, we again face panels that flat out fail with parameters they
> claim to support. Revert, and go back to the drawing board.

Yup, already multiple users facing this issue with eDP 1.4 panels that require
max parameters to pass link train.

I hear you now :)

Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>

> 
> v2: Actually revert to max params instead of just wide-and-slow.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
> Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Manasi Navare <manasi.d.navare@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Matt Atwood <matthew.s.atwood@intel.com>
> Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
> Cc: Dave Airlie <airlied@gmail.com>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v5.0+
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
>  1 file changed, 10 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 72c490..dfa770 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
>  	return -EINVAL;
>  }
>  
> -/* Optimize link config in order: max bpp, min lanes, min clock */
> -static int
> -intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> -				  struct intel_crtc_state *pipe_config,
> -				  const struct link_config_limits *limits)
> -{
> -	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> -	int bpp, clock, lane_count;
> -	int mode_rate, link_clock, link_avail;
> -
> -	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
> -		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> -						   bpp);
> -
> -		for (lane_count = limits->min_lane_count;
> -		     lane_count <= limits->max_lane_count;
> -		     lane_count <<= 1) {
> -			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
> -				link_clock = intel_dp->common_rates[clock];
> -				link_avail = intel_dp_max_data_rate(link_clock,
> -								    lane_count);
> -
> -				if (mode_rate <= link_avail) {
> -					pipe_config->lane_count = lane_count;
> -					pipe_config->pipe_bpp = bpp;
> -					pipe_config->port_clock = link_clock;
> -
> -					return 0;
> -				}
> -			}
> -		}
> -	}
> -
> -	return -EINVAL;
> -}
> -
>  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
>  {
>  	int i, num_bpc;
> @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  	limits.min_bpp = 6 * 3;
>  	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
>  
> -	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> +	if (intel_dp_is_edp(intel_dp)) {
>  		/*
>  		 * Use the maximum clock and number of lanes the eDP panel
> -		 * advertizes being capable of. The eDP 1.3 and earlier panels
> -		 * are generally designed to support only a single clock and
> -		 * lane configuration, and typically these values correspond to
> -		 * the native resolution of the panel. With eDP 1.4 rate select
> -		 * and DSC, this is decreasingly the case, and we need to be
> -		 * able to select less than maximum link config.
> +		 * advertizes being capable of. The panels are generally
> +		 * designed to support only a single clock and lane
> +		 * configuration, and typically these values correspond to the
> +		 * native resolution of the panel.
>  		 */
>  		limits.min_lane_count = limits.max_lane_count;
>  		limits.min_clock = limits.max_clock;
> @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  		      intel_dp->common_rates[limits.max_clock],
>  		      limits.max_bpp, adjusted_mode->crtc_clock);
>  
> -	if (intel_dp_is_edp(intel_dp))
> -		/*
> -		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> -		 * section A.1: "It is recommended that the minimum number of
> -		 * lanes be used, using the minimum link rate allowed for that
> -		 * lane configuration."
> -		 *
> -		 * Note that we use the max clock and lane count for eDP 1.3 and
> -		 * earlier, and fast vs. wide is irrelevant.
> -		 */
> -		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> -							&limits);
> -	else
> -		/* Optimize for slow and wide. */
> -		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> -							&limits);
> +	/*
> +	 * Optimize for slow and wide. This is the place to add alternative
> +	 * optimization policy.
> +	 */
> +	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
>  
>  	/* enable compression if the mode doesn't fit available BW */
>  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> -- 
> 2.20.1
>
Rodrigo Vivi April 5, 2019, 8:13 p.m. UTC | #3
On Fri, Apr 05, 2019 at 11:18:25AM -0700, Manasi Navare wrote:
> On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
> > Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
> > and narrow") started to optize the eDP 1.4+ link config, both per spec
> > and as preparation for display stream compression support.
> > 
> > Sadly, we again face panels that flat out fail with parameters they
> > claim to support. Revert, and go back to the drawing board.
> 
> Yup, already multiple users facing this issue with eDP 1.4 panels that require
> max parameters to pass link train.

I was wondering if we should blacklist the panel/platform, but if
there are multiple cases it is better to revert...

Unless there's a way to try and fallback quickly?!

> 
> I hear you now :)
> 
> Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
> 
> > 
> > v2: Actually revert to max params instead of just wide-and-slow.
> > 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
> > Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Cc: Matt Atwood <matthew.s.atwood@intel.com>
> > Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
> > Cc: Dave Airlie <airlied@gmail.com>
> > Cc: intel-gfx@lists.freedesktop.org
> > Cc: <stable@vger.kernel.org> # v5.0+
> > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
> >  1 file changed, 10 insertions(+), 59 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index 72c490..dfa770 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> >  	return -EINVAL;
> >  }
> >  
> > -/* Optimize link config in order: max bpp, min lanes, min clock */
> > -static int
> > -intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> > -				  struct intel_crtc_state *pipe_config,
> > -				  const struct link_config_limits *limits)
> > -{
> > -	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> > -	int bpp, clock, lane_count;
> > -	int mode_rate, link_clock, link_avail;
> > -
> > -	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
> > -		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> > -						   bpp);
> > -
> > -		for (lane_count = limits->min_lane_count;
> > -		     lane_count <= limits->max_lane_count;
> > -		     lane_count <<= 1) {
> > -			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
> > -				link_clock = intel_dp->common_rates[clock];
> > -				link_avail = intel_dp_max_data_rate(link_clock,
> > -								    lane_count);
> > -
> > -				if (mode_rate <= link_avail) {
> > -					pipe_config->lane_count = lane_count;
> > -					pipe_config->pipe_bpp = bpp;
> > -					pipe_config->port_clock = link_clock;
> > -
> > -					return 0;
> > -				}
> > -			}
> > -		}
> > -	}
> > -
> > -	return -EINVAL;
> > -}
> > -
> >  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> >  {
> >  	int i, num_bpc;
> > @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  	limits.min_bpp = 6 * 3;
> >  	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
> >  
> > -	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> > +	if (intel_dp_is_edp(intel_dp)) {
> >  		/*
> >  		 * Use the maximum clock and number of lanes the eDP panel
> > -		 * advertizes being capable of. The eDP 1.3 and earlier panels
> > -		 * are generally designed to support only a single clock and
> > -		 * lane configuration, and typically these values correspond to
> > -		 * the native resolution of the panel. With eDP 1.4 rate select
> > -		 * and DSC, this is decreasingly the case, and we need to be
> > -		 * able to select less than maximum link config.
> > +		 * advertizes being capable of. The panels are generally
> > +		 * designed to support only a single clock and lane
> > +		 * configuration, and typically these values correspond to the
> > +		 * native resolution of the panel.
> >  		 */
> >  		limits.min_lane_count = limits.max_lane_count;
> >  		limits.min_clock = limits.max_clock;
> > @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  		      intel_dp->common_rates[limits.max_clock],
> >  		      limits.max_bpp, adjusted_mode->crtc_clock);
> >  
> > -	if (intel_dp_is_edp(intel_dp))
> > -		/*
> > -		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> > -		 * section A.1: "It is recommended that the minimum number of
> > -		 * lanes be used, using the minimum link rate allowed for that
> > -		 * lane configuration."
> > -		 *
> > -		 * Note that we use the max clock and lane count for eDP 1.3 and
> > -		 * earlier, and fast vs. wide is irrelevant.
> > -		 */
> > -		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> > -							&limits);
> > -	else
> > -		/* Optimize for slow and wide. */
> > -		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> > -							&limits);
> > +	/*
> > +	 * Optimize for slow and wide. This is the place to add alternative
> > +	 * optimization policy.
> > +	 */
> > +	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
> >  
> >  	/* enable compression if the mode doesn't fit available BW */
> >  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> > -- 
> > 2.20.1
> >
Navare, Manasi April 5, 2019, 8:20 p.m. UTC | #4
On Fri, Apr 05, 2019 at 01:13:11PM -0700, Rodrigo Vivi wrote:
> On Fri, Apr 05, 2019 at 11:18:25AM -0700, Manasi Navare wrote:
> > On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
> > > Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
> > > and narrow") started to optize the eDP 1.4+ link config, both per spec
> > > and as preparation for display stream compression support.
> > > 
> > > Sadly, we again face panels that flat out fail with parameters they
> > > claim to support. Revert, and go back to the drawing board.
> > 
> > Yup, already multiple users facing this issue with eDP 1.4 panels that require
> > max parameters to pass link train.
> 
> I was wondering if we should blacklist the panel/platform, but if
> there are multiple cases it is better to revert...

Yes the bug has been reported and seen by atleast 4 users on different eDP panel product IDs

> 
> Unless there's a way to try and fallback quickly?!

I submitted a patch earlier to fallback with max parameters if optimized ones dont work:
https://patchwork.freedesktop.org/patch/296273/?series=58975&rev=2

But airlied suugested a revert instead.

Manasi

> 
> > 
> > I hear you now :)
> > 
> > Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
> > 
> > > 
> > > v2: Actually revert to max params instead of just wide-and-slow.
> > > 
> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
> > > Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
> > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > Cc: Matt Atwood <matthew.s.atwood@intel.com>
> > > Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
> > > Cc: Dave Airlie <airlied@gmail.com>
> > > Cc: intel-gfx@lists.freedesktop.org
> > > Cc: <stable@vger.kernel.org> # v5.0+
> > > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
> > >  1 file changed, 10 insertions(+), 59 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > index 72c490..dfa770 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> > >  	return -EINVAL;
> > >  }
> > >  
> > > -/* Optimize link config in order: max bpp, min lanes, min clock */
> > > -static int
> > > -intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> > > -				  struct intel_crtc_state *pipe_config,
> > > -				  const struct link_config_limits *limits)
> > > -{
> > > -	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> > > -	int bpp, clock, lane_count;
> > > -	int mode_rate, link_clock, link_avail;
> > > -
> > > -	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
> > > -		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> > > -						   bpp);
> > > -
> > > -		for (lane_count = limits->min_lane_count;
> > > -		     lane_count <= limits->max_lane_count;
> > > -		     lane_count <<= 1) {
> > > -			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
> > > -				link_clock = intel_dp->common_rates[clock];
> > > -				link_avail = intel_dp_max_data_rate(link_clock,
> > > -								    lane_count);
> > > -
> > > -				if (mode_rate <= link_avail) {
> > > -					pipe_config->lane_count = lane_count;
> > > -					pipe_config->pipe_bpp = bpp;
> > > -					pipe_config->port_clock = link_clock;
> > > -
> > > -					return 0;
> > > -				}
> > > -			}
> > > -		}
> > > -	}
> > > -
> > > -	return -EINVAL;
> > > -}
> > > -
> > >  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> > >  {
> > >  	int i, num_bpc;
> > > @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> > >  	limits.min_bpp = 6 * 3;
> > >  	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
> > >  
> > > -	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> > > +	if (intel_dp_is_edp(intel_dp)) {
> > >  		/*
> > >  		 * Use the maximum clock and number of lanes the eDP panel
> > > -		 * advertizes being capable of. The eDP 1.3 and earlier panels
> > > -		 * are generally designed to support only a single clock and
> > > -		 * lane configuration, and typically these values correspond to
> > > -		 * the native resolution of the panel. With eDP 1.4 rate select
> > > -		 * and DSC, this is decreasingly the case, and we need to be
> > > -		 * able to select less than maximum link config.
> > > +		 * advertizes being capable of. The panels are generally
> > > +		 * designed to support only a single clock and lane
> > > +		 * configuration, and typically these values correspond to the
> > > +		 * native resolution of the panel.
> > >  		 */
> > >  		limits.min_lane_count = limits.max_lane_count;
> > >  		limits.min_clock = limits.max_clock;
> > > @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> > >  		      intel_dp->common_rates[limits.max_clock],
> > >  		      limits.max_bpp, adjusted_mode->crtc_clock);
> > >  
> > > -	if (intel_dp_is_edp(intel_dp))
> > > -		/*
> > > -		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> > > -		 * section A.1: "It is recommended that the minimum number of
> > > -		 * lanes be used, using the minimum link rate allowed for that
> > > -		 * lane configuration."
> > > -		 *
> > > -		 * Note that we use the max clock and lane count for eDP 1.3 and
> > > -		 * earlier, and fast vs. wide is irrelevant.
> > > -		 */
> > > -		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> > > -							&limits);
> > > -	else
> > > -		/* Optimize for slow and wide. */
> > > -		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> > > -							&limits);
> > > +	/*
> > > +	 * Optimize for slow and wide. This is the place to add alternative
> > > +	 * optimization policy.
> > > +	 */
> > > +	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
> > >  
> > >  	/* enable compression if the mode doesn't fit available BW */
> > >  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> > > -- 
> > > 2.20.1
> > >
Sasha Levin April 8, 2019, 2:53 p.m. UTC | #5
Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: 7769db588384 drm/i915/dp: optimize eDP 1.4+ link config fast and narrow.

The bot has tested the following trees: v5.0.7.

v5.0.7: Failed to apply! Possible dependencies:
    204474a6b859 ("drm/i915: Pass down rc in intel_encoder->compute_config()")
    e845f099f1c6 ("drm/i915/dsc: Add Per connector debugfs node for DSC support/enable")
    f6bff60e927b ("drm/i915/icl: Fix HPD handling for TypeC legacy ports")


How should we proceed with this patch?

--
Thanks,
Sasha
Jani Nikula April 10, 2019, 12:54 p.m. UTC | #6
On Fri, 05 Apr 2019, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
>> Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
>> and narrow") started to optize the eDP 1.4+ link config, both per spec
>> and as preparation for display stream compression support.
>> 
>> Sadly, we again face panels that flat out fail with parameters they
>> claim to support. Revert, and go back to the drawing board.
>> 
>> v2: Actually revert to max params instead of just wide-and-slow.
>> 
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
>> Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Cc: Manasi Navare <manasi.d.navare@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> Cc: Matt Atwood <matthew.s.atwood@intel.com>
>> Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
>> Cc: Dave Airlie <airlied@gmail.com>
>> Cc: intel-gfx@lists.freedesktop.org
>> Cc: <stable@vger.kernel.org> # v5.0+
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> I can hear from here your "I told you so"... Sorry!
>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Thanks, pushed, please cherry-pick this for drm-intel-fixes.

BR,
Jani.



>
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
>>  1 file changed, 10 insertions(+), 59 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index 72c490..dfa770 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
>>  	return -EINVAL;
>>  }
>>  
>> -/* Optimize link config in order: max bpp, min lanes, min clock */
>> -static int
>> -intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
>> -				  struct intel_crtc_state *pipe_config,
>> -				  const struct link_config_limits *limits)
>> -{
>> -	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
>> -	int bpp, clock, lane_count;
>> -	int mode_rate, link_clock, link_avail;
>> -
>> -	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
>> -		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
>> -						   bpp);
>> -
>> -		for (lane_count = limits->min_lane_count;
>> -		     lane_count <= limits->max_lane_count;
>> -		     lane_count <<= 1) {
>> -			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
>> -				link_clock = intel_dp->common_rates[clock];
>> -				link_avail = intel_dp_max_data_rate(link_clock,
>> -								    lane_count);
>> -
>> -				if (mode_rate <= link_avail) {
>> -					pipe_config->lane_count = lane_count;
>> -					pipe_config->pipe_bpp = bpp;
>> -					pipe_config->port_clock = link_clock;
>> -
>> -					return 0;
>> -				}
>> -			}
>> -		}
>> -	}
>> -
>> -	return -EINVAL;
>> -}
>> -
>>  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
>>  {
>>  	int i, num_bpc;
>> @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>>  	limits.min_bpp = 6 * 3;
>>  	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
>>  
>> -	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
>> +	if (intel_dp_is_edp(intel_dp)) {
>>  		/*
>>  		 * Use the maximum clock and number of lanes the eDP panel
>> -		 * advertizes being capable of. The eDP 1.3 and earlier panels
>> -		 * are generally designed to support only a single clock and
>> -		 * lane configuration, and typically these values correspond to
>> -		 * the native resolution of the panel. With eDP 1.4 rate select
>> -		 * and DSC, this is decreasingly the case, and we need to be
>> -		 * able to select less than maximum link config.
>> +		 * advertizes being capable of. The panels are generally
>> +		 * designed to support only a single clock and lane
>> +		 * configuration, and typically these values correspond to the
>> +		 * native resolution of the panel.
>>  		 */
>>  		limits.min_lane_count = limits.max_lane_count;
>>  		limits.min_clock = limits.max_clock;
>> @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>>  		      intel_dp->common_rates[limits.max_clock],
>>  		      limits.max_bpp, adjusted_mode->crtc_clock);
>>  
>> -	if (intel_dp_is_edp(intel_dp))
>> -		/*
>> -		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
>> -		 * section A.1: "It is recommended that the minimum number of
>> -		 * lanes be used, using the minimum link rate allowed for that
>> -		 * lane configuration."
>> -		 *
>> -		 * Note that we use the max clock and lane count for eDP 1.3 and
>> -		 * earlier, and fast vs. wide is irrelevant.
>> -		 */
>> -		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
>> -							&limits);
>> -	else
>> -		/* Optimize for slow and wide. */
>> -		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
>> -							&limits);
>> +	/*
>> +	 * Optimize for slow and wide. This is the place to add alternative
>> +	 * optimization policy.
>> +	 */
>> +	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
>>  
>>  	/* enable compression if the mode doesn't fit available BW */
>>  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
>> -- 
>> 2.20.1
>>
Rodrigo Vivi April 10, 2019, 6 p.m. UTC | #7
On Wed, Apr 10, 2019 at 03:54:23PM +0300, Jani Nikula wrote:
> On Fri, 05 Apr 2019, Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:
> > On Fri, Apr 05, 2019 at 10:52:20AM +0300, Jani Nikula wrote:
> >> Commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast
> >> and narrow") started to optize the eDP 1.4+ link config, both per spec
> >> and as preparation for display stream compression support.
> >> 
> >> Sadly, we again face panels that flat out fail with parameters they
> >> claim to support. Revert, and go back to the drawing board.
> >> 
> >> v2: Actually revert to max params instead of just wide-and-slow.
> >> 
> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109959
> >> Fixes: 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config fast and narrow")
> >> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >> Cc: Manasi Navare <manasi.d.navare@intel.com>
> >> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> >> Cc: Matt Atwood <matthew.s.atwood@intel.com>
> >> Cc: "Lee, Shawn C" <shawn.c.lee@intel.com>
> >> Cc: Dave Airlie <airlied@gmail.com>
> >> Cc: intel-gfx@lists.freedesktop.org
> >> Cc: <stable@vger.kernel.org> # v5.0+
> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> >
> > I can hear from here your "I told you so"... Sorry!
> >
> > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> 
> Thanks, pushed, please cherry-pick this for drm-intel-fixes.

done. going on tomorrow's pull request...

> 
> BR,
> Jani.
> 
> 
> 
> >
> >> ---
> >>  drivers/gpu/drm/i915/intel_dp.c | 69 +++++----------------------------
> >>  1 file changed, 10 insertions(+), 59 deletions(-)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >> index 72c490..dfa770 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp.c
> >> @@ -1856,42 +1856,6 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> >>  	return -EINVAL;
> >>  }
> >>  
> >> -/* Optimize link config in order: max bpp, min lanes, min clock */
> >> -static int
> >> -intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> >> -				  struct intel_crtc_state *pipe_config,
> >> -				  const struct link_config_limits *limits)
> >> -{
> >> -	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> >> -	int bpp, clock, lane_count;
> >> -	int mode_rate, link_clock, link_avail;
> >> -
> >> -	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
> >> -		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
> >> -						   bpp);
> >> -
> >> -		for (lane_count = limits->min_lane_count;
> >> -		     lane_count <= limits->max_lane_count;
> >> -		     lane_count <<= 1) {
> >> -			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
> >> -				link_clock = intel_dp->common_rates[clock];
> >> -				link_avail = intel_dp_max_data_rate(link_clock,
> >> -								    lane_count);
> >> -
> >> -				if (mode_rate <= link_avail) {
> >> -					pipe_config->lane_count = lane_count;
> >> -					pipe_config->pipe_bpp = bpp;
> >> -					pipe_config->port_clock = link_clock;
> >> -
> >> -					return 0;
> >> -				}
> >> -			}
> >> -		}
> >> -	}
> >> -
> >> -	return -EINVAL;
> >> -}
> >> -
> >>  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> >>  {
> >>  	int i, num_bpc;
> >> @@ -2028,15 +1992,13 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >>  	limits.min_bpp = 6 * 3;
> >>  	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
> >>  
> >> -	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
> >> +	if (intel_dp_is_edp(intel_dp)) {
> >>  		/*
> >>  		 * Use the maximum clock and number of lanes the eDP panel
> >> -		 * advertizes being capable of. The eDP 1.3 and earlier panels
> >> -		 * are generally designed to support only a single clock and
> >> -		 * lane configuration, and typically these values correspond to
> >> -		 * the native resolution of the panel. With eDP 1.4 rate select
> >> -		 * and DSC, this is decreasingly the case, and we need to be
> >> -		 * able to select less than maximum link config.
> >> +		 * advertizes being capable of. The panels are generally
> >> +		 * designed to support only a single clock and lane
> >> +		 * configuration, and typically these values correspond to the
> >> +		 * native resolution of the panel.
> >>  		 */
> >>  		limits.min_lane_count = limits.max_lane_count;
> >>  		limits.min_clock = limits.max_clock;
> >> @@ -2050,22 +2012,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >>  		      intel_dp->common_rates[limits.max_clock],
> >>  		      limits.max_bpp, adjusted_mode->crtc_clock);
> >>  
> >> -	if (intel_dp_is_edp(intel_dp))
> >> -		/*
> >> -		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
> >> -		 * section A.1: "It is recommended that the minimum number of
> >> -		 * lanes be used, using the minimum link rate allowed for that
> >> -		 * lane configuration."
> >> -		 *
> >> -		 * Note that we use the max clock and lane count for eDP 1.3 and
> >> -		 * earlier, and fast vs. wide is irrelevant.
> >> -		 */
> >> -		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
> >> -							&limits);
> >> -	else
> >> -		/* Optimize for slow and wide. */
> >> -		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
> >> -							&limits);
> >> +	/*
> >> +	 * Optimize for slow and wide. This is the place to add alternative
> >> +	 * optimization policy.
> >> +	 */
> >> +	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
> >>  
> >>  	/* enable compression if the mode doesn't fit available BW */
> >>  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> >> -- 
> >> 2.20.1
> >> 
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 72c490..dfa770 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1856,42 +1856,6 @@  intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
 	return -EINVAL;
 }
 
-/* Optimize link config in order: max bpp, min lanes, min clock */
-static int
-intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
-				  struct intel_crtc_state *pipe_config,
-				  const struct link_config_limits *limits)
-{
-	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
-	int bpp, clock, lane_count;
-	int mode_rate, link_clock, link_avail;
-
-	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
-		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
-						   bpp);
-
-		for (lane_count = limits->min_lane_count;
-		     lane_count <= limits->max_lane_count;
-		     lane_count <<= 1) {
-			for (clock = limits->min_clock; clock <= limits->max_clock; clock++) {
-				link_clock = intel_dp->common_rates[clock];
-				link_avail = intel_dp_max_data_rate(link_clock,
-								    lane_count);
-
-				if (mode_rate <= link_avail) {
-					pipe_config->lane_count = lane_count;
-					pipe_config->pipe_bpp = bpp;
-					pipe_config->port_clock = link_clock;
-
-					return 0;
-				}
-			}
-		}
-	}
-
-	return -EINVAL;
-}
-
 static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
 {
 	int i, num_bpc;
@@ -2028,15 +1992,13 @@  intel_dp_compute_link_config(struct intel_encoder *encoder,
 	limits.min_bpp = 6 * 3;
 	limits.max_bpp = intel_dp_compute_bpp(intel_dp, pipe_config);
 
-	if (intel_dp_is_edp(intel_dp) && intel_dp->edp_dpcd[0] < DP_EDP_14) {
+	if (intel_dp_is_edp(intel_dp)) {
 		/*
 		 * Use the maximum clock and number of lanes the eDP panel
-		 * advertizes being capable of. The eDP 1.3 and earlier panels
-		 * are generally designed to support only a single clock and
-		 * lane configuration, and typically these values correspond to
-		 * the native resolution of the panel. With eDP 1.4 rate select
-		 * and DSC, this is decreasingly the case, and we need to be
-		 * able to select less than maximum link config.
+		 * advertizes being capable of. The panels are generally
+		 * designed to support only a single clock and lane
+		 * configuration, and typically these values correspond to the
+		 * native resolution of the panel.
 		 */
 		limits.min_lane_count = limits.max_lane_count;
 		limits.min_clock = limits.max_clock;
@@ -2050,22 +2012,11 @@  intel_dp_compute_link_config(struct intel_encoder *encoder,
 		      intel_dp->common_rates[limits.max_clock],
 		      limits.max_bpp, adjusted_mode->crtc_clock);
 
-	if (intel_dp_is_edp(intel_dp))
-		/*
-		 * Optimize for fast and narrow. eDP 1.3 section 3.3 and eDP 1.4
-		 * section A.1: "It is recommended that the minimum number of
-		 * lanes be used, using the minimum link rate allowed for that
-		 * lane configuration."
-		 *
-		 * Note that we use the max clock and lane count for eDP 1.3 and
-		 * earlier, and fast vs. wide is irrelevant.
-		 */
-		ret = intel_dp_compute_link_config_fast(intel_dp, pipe_config,
-							&limits);
-	else
-		/* Optimize for slow and wide. */
-		ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config,
-							&limits);
+	/*
+	 * Optimize for slow and wide. This is the place to add alternative
+	 * optimization policy.
+	 */
+	ret = intel_dp_compute_link_config_wide(intel_dp, pipe_config, &limits);
 
 	/* enable compression if the mode doesn't fit available BW */
 	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);