[LUCID SRU] request pull i915: fix ironlake edp panel setup (v4)

[Manoj Iyer]

FYI: stable patch is on gkh queue, as per his email.


Cheers
--- manjo

On Wed, 11 Aug 2010, Manoj Iyer wrote:

>
> BUG
> ===
> http://launchpad.net/bugs/561802
>
> SRU JUSTIFICATION
> ================
> During installation, bootup (plymouth) and while inside X, screen remains
> blank. Switching VTs yields no results (screen remains blank). This patch
> is required to fix this issue.
>
> TESTING
> =======
> The patch was tested by James Ferguson @ canonical on E6510 and E6410 and
> reported to work. It does introduce any regressions on other systems I
> tested.
>
> PATCH
> =====
> The patch is not readily application from upstream to Lucid, it needs to
> be back ported. I have already submitted the patch to stable at kernel.org for
> stable inclusion 3.6.34.y.
>
> The following changes since commit
> f093f69b09ba908509e031d9578e92b2ce8d3582:
>   Adam Jackson (1):
>         drm/i915: Make G4X-style PLL search more permissive
>
> are available in the git repository at:
>
>
> git://kernel.ubuntu.com/git/manjo/ubuntu-lucid.git lp561802
>
> Dave Airlie (1):
>       i915: fix ironlake edp panel setup (v4)
>
>  drivers/gpu/drm/i915/intel_dp.c |   27 ++++++++++++++++++++++++---
>  1 files changed, 24 insertions(+), 3 deletions(-)
>
> From 39d72c68727400af464103d209fe0dcba832b21f Mon Sep 17 00:00:00 2001
> From: Dave Airlie <airlied at redhat.com>
> Date: Wed, 30 Jun 2010 11:46:17 +1000
> Subject: [PATCH] i915: fix ironlake edp panel setup (v4)
>
> The eDP spec claims a 20% overhead for the 8:10 encoding scheme used
> on the wire. Take this into account when picking the lane/clock speed
> for the panel.
>
> v3: some panels are out of spec, try our best to deal with them, don't
> refuse modes on eDP panels, and try the largest allowed settings if
> all else fails on eDP.
> v4: fix stupid typo, forgot to git add before amending.
>
> Fixes several reports in bugzilla:
>
>       https://bugs.freedesktop.org/show_bug.cgi?id=28070
>
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> Signed-off-by: Eric Anholt <eric at anholt.net>
> Signed-off-by: Manoj Iyer <manoj.iyer at canonical.com>
>
> Buglink: http://launchpad.net/bugs/561802
>
> This patch is backported from upstream patch SHAID: fe27d53e5c597ee5ba5d72a29d517091f244e974
> ---
>  drivers/gpu/drm/i915/intel_dp.c |   27 ++++++++++++++++++++++++---
>  1 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 6b62762..63ea21e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -137,6 +137,12 @@ intel_dp_link_required(struct drm_device *dev,
>  }
>
>  static int
> +intel_dp_max_data_rate(int max_link_clock, int max_lanes)
> +{
> +	return (max_link_clock * max_lanes * 8) / 10;
> +}
> +
> +static int
>  intel_dp_mode_valid(struct drm_connector *connector,
>  		    struct drm_display_mode *mode)
>  {
> @@ -144,8 +150,11 @@ intel_dp_mode_valid(struct drm_connector *connector,
>  	int max_link_clock = intel_dp_link_clock(intel_dp_max_link_bw(intel_output));
>  	int max_lanes = intel_dp_max_lane_count(intel_output);
>
> -	if (intel_dp_link_required(connector->dev, intel_output, mode->clock)
> -			> max_link_clock * max_lanes)
> +	/* only refuse the mode on non eDP since we have seen some wierd eDP panels
> +	   which are outside spec tolerances but somehow work by magic */
> +	if (!IS_eDP(intel_output) &&
> +	    (intel_dp_link_required(connector->dev, intel_output, mode->clock)
> +	     > intel_dp_max_data_rate(max_link_clock, max_lanes)))
>  		return MODE_CLOCK_HIGH;
>
>  	if (mode->clock < 10000)
> @@ -497,7 +506,7 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
>
>  	for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
>  		for (clock = 0; clock <= max_clock; clock++) {
> -			int link_avail = intel_dp_link_clock(bws[clock]) * lane_count;
> +			int link_avail = intel_dp_max_data_rate(intel_dp_link_clock(bws[clock]), lane_count);
>
>  			if (intel_dp_link_required(encoder->dev, intel_output, mode->clock)
>  					<= link_avail) {
> @@ -512,6 +521,18 @@ intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
>  			}
>  		}
>  	}
> +
> +	if (IS_eDP(intel_output)) {
> +		/* okay we failed just pick the highest */
> +		dp_priv->lane_count = max_lane_count;
> +		dp_priv->link_bw = bws[max_clock];
> +		adjusted_mode->clock = intel_dp_link_clock(dp_priv->link_bw);
> +		DRM_DEBUG_KMS("Force picking display port link bw %02x lane "
> +			      "count %d clock %d\n",
> +			      dp_priv->link_bw, dp_priv->lane_count,
> +			      adjusted_mode->clock);
> +		return true;
> +	}
>  	return false;
>  }
>
> -- 
> 1.7.0.4
>
>
>
> Cheers
> --- manjo
>
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