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Date:   Wed, 16 Jan 2019 11:19:40 +0100
From:   Daniel Vetter <daniel@ffwll.ch>
To:     Jani Nikula <jani.nikula@linux.intel.com>
Cc:     Lyude Paul <lyude@redhat.com>, intel-gfx@lists.freedesktop.org,
        Ville =?iso-8859-1?Q?Syrj=E4l=E4?= 
        <ville.syrjala@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] drm/i915: Pass down rc in
 intel_encoder->compute_config()
Message-ID: <20190116101940.GT10517@phenom.ffwll.local>
Mail-Followup-To: Jani Nikula <jani.nikula@linux.intel.com>,
        Lyude Paul <lyude@redhat.com>, intel-gfx@lists.freedesktop.org,
        Ville =?iso-8859-1?Q?Syrj=E4l=E4?= <ville.syrjala@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        David Airlie <airlied@linux.ie>, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
References: <20190115200800.3121-1-lyude@redhat.com>
 <87r2dd59iy.fsf@intel.com>
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On Wed, Jan 16, 2019 at 09:47:17AM +0200, Jani Nikula wrote:
> On Tue, 15 Jan 2019, Lyude Paul <lyude@redhat.com> wrote:
> > Something that I completely missed when implementing the new MST VCPI
> > atomic helpers is that with those helpers, there's technically a chance
> > of us having to grab additional modeset locks in ->compute_config() and
> > furthermore, that means we have the potential to hit a normal modeset
> > deadlock. However, because ->compute_config() only returns a bool this
> > means we can't return -EDEADLK when we need to drop locks and try again
> > which means we end up just failing the atomic check permanently. Whoops.
> >
> > So, fix this by modifying ->compute_config() to pass down an actual
> > error code instead of a bool so that the atomic check can be restarted
> > on modeset deadlocks.
> >
> > Thanks to Ville Syrj?l? for pointing this out!
> >
> > Changes since v1:
> > * Add some newlines
> > * Return only -EINVAL from hsw_crt_compute_config()
> > * Propogate return code from intel_dp_compute_dsc_params()
> > * Change all of the intel_dp_compute_link_config*() variants
> > * Don't miss if (hdmi_port_clock_valid()) branch in
> >   intel_hdmi_compute_config()
> >
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > Cc: Ville Syrj?l? <ville.syrjala@linux.intel.com>
> > Fixes: eceae1472467 ("drm/dp_mst: Start tracking per-port VCPI allocations")
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109320
> > ---
> >  drivers/gpu/drm/i915/icl_dsi.c       |  8 ++--
> >  drivers/gpu/drm/i915/intel_crt.c     | 35 +++++++-------
> >  drivers/gpu/drm/i915/intel_ddi.c     |  6 +--
> >  drivers/gpu/drm/i915/intel_display.c | 11 +++--
> >  drivers/gpu/drm/i915/intel_dp.c      | 71 +++++++++++++++-------------
> >  drivers/gpu/drm/i915/intel_dp_mst.c  | 12 ++---
> >  drivers/gpu/drm/i915/intel_drv.h     | 18 +++----
> >  drivers/gpu/drm/i915/intel_dvo.c     | 11 +++--
> >  drivers/gpu/drm/i915/intel_hdmi.c    | 14 +++---
> >  drivers/gpu/drm/i915/intel_lvds.c    | 12 ++---
> >  drivers/gpu/drm/i915/intel_sdvo.c    | 14 +++---
> >  drivers/gpu/drm/i915/intel_tv.c      |  8 ++--
> >  drivers/gpu/drm/i915/vlv_dsi.c       | 14 +++---
> >  13 files changed, 122 insertions(+), 112 deletions(-)
> 
> Despite being an all i915 patch, this got applied to drm-misc-next,
> causing conflicts where there really should have been none. :(
> 
> I am tempted to suggest reverting and re-applying to drm-intel, because
> it will take weeks to sync both to drm-next and backmerge, and applying
> further work on top in drm-intel will just cause more trouble.
> 
> Other ideas?

We discussed this a bit on irc. I think the best option is to cherry-pick
this patch over to drm-intel-next-queued and try to get the backmerges
sorted asap.

With hindsight a topic branch for all the mst stuff would have been really
good choice. And as Jani mentioned on irc, pls get maintainer's ack when
merging stuff through different trees. I wanted to ask about that but
figured I have time until nouveau stuff is reviewed, but then it landed
right away. Anyway, conflict isn't bad enough that sfr couldn't handle it,
so we didn't screw up too badly :-)

Thanks, Daniel
> 
> BR,
> Jani.
> 
> 
> >
> > diff --git a/drivers/gpu/drm/i915/icl_dsi.c b/drivers/gpu/drm/i915/icl_dsi.c
> > index f3a5f03646ce..355b48d1c937 100644
> > --- a/drivers/gpu/drm/i915/icl_dsi.c
> > +++ b/drivers/gpu/drm/i915/icl_dsi.c
> > @@ -1188,9 +1188,9 @@ static void gen11_dsi_get_config(struct intel_encoder *encoder,
> >  	pipe_config->output_types |= BIT(INTEL_OUTPUT_DSI);
> >  }
> >  
> > -static bool gen11_dsi_compute_config(struct intel_encoder *encoder,
> > -				     struct intel_crtc_state *pipe_config,
> > -				     struct drm_connector_state *conn_state)
> > +static int gen11_dsi_compute_config(struct intel_encoder *encoder,
> > +				    struct intel_crtc_state *pipe_config,
> > +				    struct drm_connector_state *conn_state)
> >  {
> >  	struct intel_dsi *intel_dsi = container_of(encoder, struct intel_dsi,
> >  						   base);
> > @@ -1215,7 +1215,7 @@ static bool gen11_dsi_compute_config(struct intel_encoder *encoder,
> >  	pipe_config->clock_set = true;
> >  	pipe_config->port_clock = intel_dsi_bitrate(intel_dsi) / 5;
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static u64 gen11_dsi_get_power_domains(struct intel_encoder *encoder,
> > diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
> > index 33bd2addcbdd..081c333f30d2 100644
> > --- a/drivers/gpu/drm/i915/intel_crt.c
> > +++ b/drivers/gpu/drm/i915/intel_crt.c
> > @@ -345,51 +345,52 @@ intel_crt_mode_valid(struct drm_connector *connector,
> >  	return MODE_OK;
> >  }
> >  
> > -static bool intel_crt_compute_config(struct intel_encoder *encoder,
> > -				     struct intel_crtc_state *pipe_config,
> > -				     struct drm_connector_state *conn_state)
> > +static int intel_crt_compute_config(struct intel_encoder *encoder,
> > +				    struct intel_crtc_state *pipe_config,
> > +				    struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_display_mode *adjusted_mode =
> >  		&pipe_config->base.adjusted_mode;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> > -	return true;
> > +
> > +	return 0;
> >  }
> >  
> > -static bool pch_crt_compute_config(struct intel_encoder *encoder,
> > -				   struct intel_crtc_state *pipe_config,
> > -				   struct drm_connector_state *conn_state)
> > +static int pch_crt_compute_config(struct intel_encoder *encoder,
> > +				  struct intel_crtc_state *pipe_config,
> > +				  struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_display_mode *adjusted_mode =
> >  		&pipe_config->base.adjusted_mode;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->has_pch_encoder = true;
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> > -static bool hsw_crt_compute_config(struct intel_encoder *encoder,
> > -				   struct intel_crtc_state *pipe_config,
> > -				   struct drm_connector_state *conn_state)
> > +static int hsw_crt_compute_config(struct intel_encoder *encoder,
> > +				  struct intel_crtc_state *pipe_config,
> > +				  struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >  	struct drm_display_mode *adjusted_mode =
> >  		&pipe_config->base.adjusted_mode;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	/* HSW/BDW FDI limited to 4k */
> >  	if (adjusted_mode->crtc_hdisplay > 4096 ||
> >  	    adjusted_mode->crtc_hblank_start > 4096)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->has_pch_encoder = true;
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> > @@ -398,7 +399,7 @@ static bool hsw_crt_compute_config(struct intel_encoder *encoder,
> >  	if (HAS_PCH_LPT(dev_priv)) {
> >  		if (pipe_config->bw_constrained && pipe_config->pipe_bpp < 24) {
> >  			DRM_DEBUG_KMS("LPT only supports 24bpp\n");
> > -			return false;
> > +			return -EINVAL;
> >  		}
> >  
> >  		pipe_config->pipe_bpp = 24;
> > @@ -407,7 +408,7 @@ static bool hsw_crt_compute_config(struct intel_encoder *encoder,
> >  	/* FDI must always be 2.7 GHz */
> >  	pipe_config->port_clock = 135000 * 2;
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static bool intel_ironlake_crt_detect_hotplug(struct drm_connector *connector)
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 7f3cd055de50..ce44744a5f9d 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -3837,9 +3837,9 @@ intel_ddi_compute_output_type(struct intel_encoder *encoder,
> >  	}
> >  }
> >  
> > -static bool intel_ddi_compute_config(struct intel_encoder *encoder,
> > -				     struct intel_crtc_state *pipe_config,
> > -				     struct drm_connector_state *conn_state)
> > +static int intel_ddi_compute_config(struct intel_encoder *encoder,
> > +				    struct intel_crtc_state *pipe_config,
> > +				    struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >  	enum port port = encoder->port;
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 0a5ba45f5eb0..af164d712e9e 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -11553,10 +11553,13 @@ intel_modeset_pipe_config(struct drm_crtc *crtc,
> >  			continue;
> >  
> >  		encoder = to_intel_encoder(connector_state->best_encoder);
> > -
> > -		if (!(encoder->compute_config(encoder, pipe_config, connector_state))) {
> > -			DRM_DEBUG_KMS("Encoder config failure\n");
> > -			return -EINVAL;
> > +		ret = encoder->compute_config(encoder, pipe_config,
> > +					      connector_state);
> > +		if (ret < 0) {
> > +			if (ret != -EDEADLK)
> > +				DRM_DEBUG_KMS("Encoder config failure: %d\n",
> > +					      ret);
> > +			return ret;
> >  		}
> >  	}
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > index 0a3ac98a779e..df4292bb1a4f 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -1819,7 +1819,7 @@ intel_dp_adjust_compliance_config(struct intel_dp *intel_dp,
> >  }
> >  
> >  /* Optimize link config in order: max bpp, min clock, min lanes */
> > -static bool
> > +static int
> >  intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> >  				  struct intel_crtc_state *pipe_config,
> >  				  const struct link_config_limits *limits)
> > @@ -1845,17 +1845,17 @@ intel_dp_compute_link_config_wide(struct intel_dp *intel_dp,
> >  					pipe_config->pipe_bpp = bpp;
> >  					pipe_config->port_clock = link_clock;
> >  
> > -					return true;
> > +					return 0;
> >  				}
> >  			}
> >  		}
> >  	}
> >  
> > -	return false;
> > +	return -EINVAL;
> >  }
> >  
> >  /* Optimize link config in order: max bpp, min lanes, min clock */
> > -static bool
> > +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)
> > @@ -1881,13 +1881,13 @@ intel_dp_compute_link_config_fast(struct intel_dp *intel_dp,
> >  					pipe_config->pipe_bpp = bpp;
> >  					pipe_config->port_clock = link_clock;
> >  
> > -					return true;
> > +					return 0;
> >  				}
> >  			}
> >  		}
> >  	}
> >  
> > -	return false;
> > +	return -EINVAL;
> >  }
> >  
> >  static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> > @@ -1905,19 +1905,20 @@ static int intel_dp_dsc_compute_bpp(struct intel_dp *intel_dp, u8 dsc_max_bpc)
> >  	return 0;
> >  }
> >  
> > -static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > -					struct intel_crtc_state *pipe_config,
> > -					struct drm_connector_state *conn_state,
> > -					struct link_config_limits *limits)
> > +static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> > +				       struct intel_crtc_state *pipe_config,
> > +				       struct drm_connector_state *conn_state,
> > +				       struct link_config_limits *limits)
> >  {
> >  	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> >  	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> >  	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> >  	u8 dsc_max_bpc;
> >  	int pipe_bpp;
> > +	int ret;
> >  
> >  	if (!intel_dp_supports_dsc(intel_dp, pipe_config))
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	dsc_max_bpc = min_t(u8, DP_DSC_MAX_SUPPORTED_BPC,
> >  			    conn_state->max_requested_bpc);
> > @@ -1925,7 +1926,7 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> >  	pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, dsc_max_bpc);
> >  	if (pipe_bpp < DP_DSC_MIN_SUPPORTED_BPC * 3) {
> >  		DRM_DEBUG_KMS("No DSC support for less than 8bpc\n");
> > -		return false;
> > +		return -EINVAL;
> >  	}
> >  
> >  	/*
> > @@ -1959,7 +1960,7 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> >  						     adjusted_mode->crtc_hdisplay);
> >  		if (!dsc_max_output_bpp || !dsc_dp_slice_count) {
> >  			DRM_DEBUG_KMS("Compressed BPP/Slice Count not supported\n");
> > -			return false;
> > +			return -EINVAL;
> >  		}
> >  		pipe_config->dsc_params.compressed_bpp = min_t(u16,
> >  							       dsc_max_output_bpp >> 4,
> > @@ -1976,16 +1977,19 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> >  			pipe_config->dsc_params.dsc_split = true;
> >  		} else {
> >  			DRM_DEBUG_KMS("Cannot split stream to use 2 VDSC instances\n");
> > -			return false;
> > +			return -EINVAL;
> >  		}
> >  	}
> > -	if (intel_dp_compute_dsc_params(intel_dp, pipe_config) < 0) {
> > +
> > +	ret = intel_dp_compute_dsc_params(intel_dp, pipe_config);
> > +	if (ret < 0) {
> >  		DRM_DEBUG_KMS("Cannot compute valid DSC parameters for Input Bpp = %d "
> >  			      "Compressed BPP = %d\n",
> >  			      pipe_config->pipe_bpp,
> >  			      pipe_config->dsc_params.compressed_bpp);
> > -		return false;
> > +		return ret;
> >  	}
> > +
> >  	pipe_config->dsc_params.compression_enable = true;
> >  	DRM_DEBUG_KMS("DP DSC computed with Input Bpp = %d "
> >  		      "Compressed Bpp = %d Slice Count = %d\n",
> > @@ -1993,10 +1997,10 @@ static bool intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
> >  		      pipe_config->dsc_params.compressed_bpp,
> >  		      pipe_config->dsc_params.slice_count);
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> > -static bool
> > +static int
> >  intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  			     struct intel_crtc_state *pipe_config,
> >  			     struct drm_connector_state *conn_state)
> > @@ -2005,7 +2009,7 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  	struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> >  	struct link_config_limits limits;
> >  	int common_len;
> > -	bool ret;
> > +	int ret;
> >  
> >  	common_len = intel_dp_common_len_rate_limit(intel_dp,
> >  						    intel_dp->max_link_rate);
> > @@ -2063,10 +2067,11 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  
> >  	/* enable compression if the mode doesn't fit available BW */
> >  	DRM_DEBUG_KMS("Force DSC en = %d\n", intel_dp->force_dsc_en);
> > -	if (!ret || intel_dp->force_dsc_en) {
> > -		if (!intel_dp_dsc_compute_config(intel_dp, pipe_config,
> > -						 conn_state, &limits))
> > -			return false;
> > +	if (ret || intel_dp->force_dsc_en) {
> > +		ret = intel_dp_dsc_compute_config(intel_dp, pipe_config,
> > +						  conn_state, &limits);
> > +		if (ret < 0)
> > +			return ret;
> >  	}
> >  
> >  	if (pipe_config->dsc_params.compression_enable) {
> > @@ -2091,10 +2096,10 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
> >  			      intel_dp_max_data_rate(pipe_config->port_clock,
> >  						     pipe_config->lane_count));
> >  	}
> > -	return true;
> > +	return 0;
> >  }
> >  
> > -bool
> > +int
> >  intel_dp_compute_config(struct intel_encoder *encoder,
> >  			struct intel_crtc_state *pipe_config,
> >  			struct drm_connector_state *conn_state)
> > @@ -2110,6 +2115,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> >  		to_intel_digital_connector_state(conn_state);
> >  	bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
> >  					   DP_DPCD_QUIRK_CONSTANT_N);
> > +	int ret;
> >  
> >  	if (HAS_PCH_SPLIT(dev_priv) && !HAS_DDI(dev_priv) && port != PORT_A)
> >  		pipe_config->has_pch_encoder = true;
> > @@ -2131,8 +2137,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> >  				       adjusted_mode);
> >  
> >  		if (INTEL_GEN(dev_priv) >= 9) {
> > -			int ret;
> > -
> >  			ret = skl_update_scaler_crtc(pipe_config);
> >  			if (ret)
> >  				return ret;
> > @@ -2147,20 +2151,21 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> >  	}
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	if (HAS_GMCH_DISPLAY(dev_priv) &&
> >  	    adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->fec_enable = !intel_dp_is_edp(intel_dp) &&
> >  				  intel_dp_supports_fec(intel_dp, pipe_config);
> >  
> > -	if (!intel_dp_compute_link_config(encoder, pipe_config, conn_state))
> > -		return false;
> > +	ret = intel_dp_compute_link_config(encoder, pipe_config, conn_state);
> > +	if (ret < 0)
> > +		return ret;
> >  
> >  	if (intel_conn_state->broadcast_rgb == INTEL_BROADCAST_RGB_AUTO) {
> >  		/*
> > @@ -2208,7 +2213,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
> >  
> >  	intel_psr_compute_config(intel_dp, pipe_config);
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  void intel_dp_set_link_params(struct intel_dp *intel_dp,
> > diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> > index 3f83429333c7..a19699023db1 100644
> > --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> > +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> > @@ -29,9 +29,9 @@
> >  #include <drm/drm_crtc_helper.h>
> >  #include <drm/drm_edid.h>
> >  
> > -static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> > -					struct intel_crtc_state *pipe_config,
> > -					struct drm_connector_state *conn_state)
> > +static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
> > +				       struct intel_crtc_state *pipe_config,
> > +				       struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >  	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
> > @@ -52,7 +52,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  					   DP_DPCD_QUIRK_CONSTANT_N);
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> >  	pipe_config->has_pch_encoder = false;
> > @@ -89,7 +89,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  		if (slots < 0) {
> >  			DRM_DEBUG_KMS("failed finding vcpi slots:%d\n",
> >  				      slots);
> > -			return false;
> > +			return slots;
> >  		}
> >  	}
> >  
> > @@ -107,7 +107,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
> >  
> >  	intel_ddi_compute_min_voltage_level(dev_priv, pipe_config);
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static int
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 7977843ce26a..e5a436c33307 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -225,9 +225,9 @@ struct intel_encoder {
> >  	enum intel_output_type (*compute_output_type)(struct intel_encoder *,
> >  						      struct intel_crtc_state *,
> >  						      struct drm_connector_state *);
> > -	bool (*compute_config)(struct intel_encoder *,
> > -			       struct intel_crtc_state *,
> > -			       struct drm_connector_state *);
> > +	int (*compute_config)(struct intel_encoder *,
> > +			      struct intel_crtc_state *,
> > +			      struct drm_connector_state *);
> >  	void (*pre_pll_enable)(struct intel_encoder *,
> >  			       const struct intel_crtc_state *,
> >  			       const struct drm_connector_state *);
> > @@ -1816,9 +1816,9 @@ void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
> >  void intel_dp_encoder_reset(struct drm_encoder *encoder);
> >  void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);
> >  void intel_dp_encoder_flush_work(struct drm_encoder *encoder);
> > -bool intel_dp_compute_config(struct intel_encoder *encoder,
> > -			     struct intel_crtc_state *pipe_config,
> > -			     struct drm_connector_state *conn_state);
> > +int intel_dp_compute_config(struct intel_encoder *encoder,
> > +			    struct intel_crtc_state *pipe_config,
> > +			    struct drm_connector_state *conn_state);
> >  bool intel_dp_is_edp(struct intel_dp *intel_dp);
> >  bool intel_dp_is_port_edp(struct drm_i915_private *dev_priv, enum port port);
> >  enum irqreturn intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port,
> > @@ -1978,9 +1978,9 @@ void intel_hdmi_init(struct drm_i915_private *dev_priv, i915_reg_t hdmi_reg,
> >  void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
> >  			       struct intel_connector *intel_connector);
> >  struct intel_hdmi *enc_to_intel_hdmi(struct drm_encoder *encoder);
> > -bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> > -			       struct intel_crtc_state *pipe_config,
> > -			       struct drm_connector_state *conn_state);
> > +int intel_hdmi_compute_config(struct intel_encoder *encoder,
> > +			      struct intel_crtc_state *pipe_config,
> > +			      struct drm_connector_state *conn_state);
> >  bool intel_hdmi_handle_sink_scrambling(struct intel_encoder *encoder,
> >  				       struct drm_connector *connector,
> >  				       bool high_tmds_clock_ratio,
> > diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
> > index bc3c3cb57ec6..a6c82482a841 100644
> > --- a/drivers/gpu/drm/i915/intel_dvo.c
> > +++ b/drivers/gpu/drm/i915/intel_dvo.c
> > @@ -234,9 +234,9 @@ intel_dvo_mode_valid(struct drm_connector *connector,
> >  	return intel_dvo->dev.dev_ops->mode_valid(&intel_dvo->dev, mode);
> >  }
> >  
> > -static bool intel_dvo_compute_config(struct intel_encoder *encoder,
> > -				     struct intel_crtc_state *pipe_config,
> > -				     struct drm_connector_state *conn_state)
> > +static int intel_dvo_compute_config(struct intel_encoder *encoder,
> > +				    struct intel_crtc_state *pipe_config,
> > +				    struct drm_connector_state *conn_state)
> >  {
> >  	struct intel_dvo *intel_dvo = enc_to_dvo(encoder);
> >  	const struct drm_display_mode *fixed_mode =
> > @@ -253,10 +253,11 @@ static bool intel_dvo_compute_config(struct intel_encoder *encoder,
> >  		intel_fixed_panel_mode(fixed_mode, adjusted_mode);
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> > -	return true;
> > +
> > +	return 0;
> >  }
> >  
> >  static void intel_dvo_pre_enable(struct intel_encoder *encoder,
> > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> > index 74f4021b760c..97a98e1bea56 100644
> > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > @@ -1704,9 +1704,9 @@ intel_hdmi_ycbcr420_config(struct drm_connector *connector,
> >  	return true;
> >  }
> >  
> > -bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> > -			       struct intel_crtc_state *pipe_config,
> > -			       struct drm_connector_state *conn_state)
> > +int intel_hdmi_compute_config(struct intel_encoder *encoder,
> > +			      struct intel_crtc_state *pipe_config,
> > +			      struct drm_connector_state *conn_state)
> >  {
> >  	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&encoder->base);
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > @@ -1722,7 +1722,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> >  	bool force_dvi = intel_conn_state->force_audio == HDMI_AUDIO_OFF_DVI;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> >  	pipe_config->has_hdmi_sink = !force_dvi && intel_hdmi->has_hdmi_sink;
> > @@ -1753,7 +1753,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> >  						&clock_12bpc, &clock_10bpc,
> >  						&clock_8bpc)) {
> >  			DRM_ERROR("Can't support YCBCR420 output\n");
> > -			return false;
> > +			return -EINVAL;
> >  		}
> >  	}
> >  
> > @@ -1803,7 +1803,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> >  	if (hdmi_port_clock_valid(intel_hdmi, pipe_config->port_clock,
> >  				  false, force_dvi) != MODE_OK) {
> >  		DRM_DEBUG_KMS("unsupported HDMI clock, rejecting mode\n");
> > -		return false;
> > +		return -EINVAL;
> >  	}
> >  
> >  	/* Set user selected PAR to incoming mode's member */
> > @@ -1822,7 +1822,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
> >  		}
> >  	}
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static void
> > diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> > index b01aacb5d73d..46a5dfd5cdf7 100644
> > --- a/drivers/gpu/drm/i915/intel_lvds.c
> > +++ b/drivers/gpu/drm/i915/intel_lvds.c
> > @@ -380,9 +380,9 @@ intel_lvds_mode_valid(struct drm_connector *connector,
> >  	return MODE_OK;
> >  }
> >  
> > -static bool intel_lvds_compute_config(struct intel_encoder *intel_encoder,
> > -				      struct intel_crtc_state *pipe_config,
> > -				      struct drm_connector_state *conn_state)
> > +static int intel_lvds_compute_config(struct intel_encoder *intel_encoder,
> > +				     struct intel_crtc_state *pipe_config,
> > +				     struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(intel_encoder->base.dev);
> >  	struct intel_lvds_encoder *lvds_encoder =
> > @@ -396,7 +396,7 @@ static bool intel_lvds_compute_config(struct intel_encoder *intel_encoder,
> >  	/* Should never happen!! */
> >  	if (INTEL_GEN(dev_priv) < 4 && intel_crtc->pipe == 0) {
> >  		DRM_ERROR("Can't support LVDS on pipe A\n");
> > -		return false;
> > +		return -EINVAL;
> >  	}
> >  
> >  	if (lvds_encoder->a3_power == LVDS_A3_POWER_UP)
> > @@ -422,7 +422,7 @@ static bool intel_lvds_compute_config(struct intel_encoder *intel_encoder,
> >  			       adjusted_mode);
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	if (HAS_PCH_SPLIT(dev_priv)) {
> >  		pipe_config->has_pch_encoder = true;
> > @@ -441,7 +441,7 @@ static bool intel_lvds_compute_config(struct intel_encoder *intel_encoder,
> >  	 * user's requested refresh rate.
> >  	 */
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static enum drm_connector_status
> > diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> > index 4db7aefa88f9..df2d830a7405 100644
> > --- a/drivers/gpu/drm/i915/intel_sdvo.c
> > +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> > @@ -1107,9 +1107,9 @@ static void i9xx_adjust_sdvo_tv_clock(struct intel_crtc_state *pipe_config)
> >  	pipe_config->clock_set = true;
> >  }
> >  
> > -static bool intel_sdvo_compute_config(struct intel_encoder *encoder,
> > -				      struct intel_crtc_state *pipe_config,
> > -				      struct drm_connector_state *conn_state)
> > +static int intel_sdvo_compute_config(struct intel_encoder *encoder,
> > +				     struct intel_crtc_state *pipe_config,
> > +				     struct drm_connector_state *conn_state)
> >  {
> >  	struct intel_sdvo *intel_sdvo = to_sdvo(encoder);
> >  	struct intel_sdvo_connector_state *intel_sdvo_state =
> > @@ -1134,7 +1134,7 @@ static bool intel_sdvo_compute_config(struct intel_encoder *encoder,
> >  	 */
> >  	if (IS_TV(intel_sdvo_connector)) {
> >  		if (!intel_sdvo_set_output_timings_from_mode(intel_sdvo, mode))
> > -			return false;
> > +			return -EINVAL;
> >  
> >  		(void) intel_sdvo_get_preferred_input_mode(intel_sdvo,
> >  							   intel_sdvo_connector,
> > @@ -1144,7 +1144,7 @@ static bool intel_sdvo_compute_config(struct intel_encoder *encoder,
> >  	} else if (IS_LVDS(intel_sdvo_connector)) {
> >  		if (!intel_sdvo_set_output_timings_from_mode(intel_sdvo,
> >  							     intel_sdvo_connector->base.panel.fixed_mode))
> > -			return false;
> > +			return -EINVAL;
> >  
> >  		(void) intel_sdvo_get_preferred_input_mode(intel_sdvo,
> >  							   intel_sdvo_connector,
> > @@ -1153,7 +1153,7 @@ static bool intel_sdvo_compute_config(struct intel_encoder *encoder,
> >  	}
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	/*
> >  	 * Make the CRTC code factor in the SDVO pixel multiplier.  The
> > @@ -1193,7 +1193,7 @@ static bool intel_sdvo_compute_config(struct intel_encoder *encoder,
> >  	if (intel_sdvo_connector->is_hdmi)
> >  		adjusted_mode->picture_aspect_ratio = conn_state->picture_aspect_ratio;
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  #define UPDATE_PROPERTY(input, NAME) \
> > diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
> > index d7a414ce2774..bd5536f0ec92 100644
> > --- a/drivers/gpu/drm/i915/intel_tv.c
> > +++ b/drivers/gpu/drm/i915/intel_tv.c
> > @@ -869,7 +869,7 @@ intel_tv_get_config(struct intel_encoder *encoder,
> >  	pipe_config->base.adjusted_mode.crtc_clock = pipe_config->port_clock;
> >  }
> >  
> > -static bool
> > +static int
> >  intel_tv_compute_config(struct intel_encoder *encoder,
> >  			struct intel_crtc_state *pipe_config,
> >  			struct drm_connector_state *conn_state)
> > @@ -879,10 +879,10 @@ intel_tv_compute_config(struct intel_encoder *encoder,
> >  		&pipe_config->base.adjusted_mode;
> >  
> >  	if (!tv_mode)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
> >  	adjusted_mode->crtc_clock = tv_mode->clock;
> > @@ -897,7 +897,7 @@ intel_tv_compute_config(struct intel_encoder *encoder,
> >  	 * or whether userspace is doing something stupid.
> >  	 */
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static void
> > diff --git a/drivers/gpu/drm/i915/vlv_dsi.c b/drivers/gpu/drm/i915/vlv_dsi.c
> > index d116fead8514..c247ce74b71a 100644
> > --- a/drivers/gpu/drm/i915/vlv_dsi.c
> > +++ b/drivers/gpu/drm/i915/vlv_dsi.c
> > @@ -256,9 +256,9 @@ static void band_gap_reset(struct drm_i915_private *dev_priv)
> >  	mutex_unlock(&dev_priv->sb_lock);
> >  }
> >  
> > -static bool intel_dsi_compute_config(struct intel_encoder *encoder,
> > -				     struct intel_crtc_state *pipe_config,
> > -				     struct drm_connector_state *conn_state)
> > +static int intel_dsi_compute_config(struct intel_encoder *encoder,
> > +				    struct intel_crtc_state *pipe_config,
> > +				    struct drm_connector_state *conn_state)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >  	struct intel_dsi *intel_dsi = container_of(encoder, struct intel_dsi,
> > @@ -284,7 +284,7 @@ static bool intel_dsi_compute_config(struct intel_encoder *encoder,
> >  	}
> >  
> >  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
> > -		return false;
> > +		return -EINVAL;
> >  
> >  	/* DSI uses short packets for sync events, so clear mode flags for DSI */
> >  	adjusted_mode->flags = 0;
> > @@ -302,16 +302,16 @@ static bool intel_dsi_compute_config(struct intel_encoder *encoder,
> >  
> >  		ret = bxt_dsi_pll_compute(encoder, pipe_config);
> >  		if (ret)
> > -			return false;
> > +			return -EINVAL;
> >  	} else {
> >  		ret = vlv_dsi_pll_compute(encoder, pipe_config);
> >  		if (ret)
> > -			return false;
> > +			return -EINVAL;
> >  	}
> >  
> >  	pipe_config->clock_set = true;
> >  
> > -	return true;
> > +	return 0;
> >  }
> >  
> >  static bool glk_dsi_enable_io(struct intel_encoder *encoder)
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch