Re: [PATCH 2/2] drm/i915: use lane count and link rate from VBT as minimums for eDP

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Apr 22, 2014 at 08:17:52PM +0300, Jani Nikula wrote:
> Most likely the minimums for both should be enough for enabling the
> native resolution on the eDP.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=73539
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76711
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Tested-by: Markus Blank-Burian <burian@muenster.de>

> ---
>  drivers/gpu/drm/i915/intel_dp.c | 23 ++++++++++++++++-------
>  1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 80e5598d66ed..c613da9cb1a9 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -764,8 +764,10 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>  	struct intel_crtc *intel_crtc = encoder->new_crtc;
>  	struct intel_connector *intel_connector = intel_dp->attached_connector;
>  	int lane_count, clock;
> +	int min_lane_count = 1;
>  	int max_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
>  	/* Conveniently, the link BW constants become indices with a shift...*/
> +	int min_clock = 0;
>  	int max_clock = intel_dp_max_link_bw(intel_dp) >> 3;
>  	int bpp, mode_rate;
>  	static int bws[] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7, DP_LINK_BW_5_4 };
> @@ -798,19 +800,26 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>  	/* Walk through all bpp values. Luckily they're all nicely spaced with 2
>  	 * bpc in between. */
>  	bpp = pipe_config->pipe_bpp;
> -	if (is_edp(intel_dp) && dev_priv->vbt.edp_bpp &&
> -	    dev_priv->vbt.edp_bpp < bpp) {
> -		DRM_DEBUG_KMS("clamping bpp for eDP panel to BIOS-provided %i\n",
> -			      dev_priv->vbt.edp_bpp);
> -		bpp = dev_priv->vbt.edp_bpp;
> +	if (is_edp(intel_dp)) {
> +		if (dev_priv->vbt.edp_bpp && dev_priv->vbt.edp_bpp < bpp) {
> +			DRM_DEBUG_KMS("clamping bpp for eDP panel to BIOS-provided %i\n",
> +				      dev_priv->vbt.edp_bpp);
> +			bpp = dev_priv->vbt.edp_bpp;
> +		}
> +
> +		if (dev_priv->vbt.edp_lanes)
> +			min_lane_count = min(dev_priv->vbt.edp_lanes,
> +					     max_lane_count);
> +		if (dev_priv->vbt.edp_rate)
> +			min_clock = min(dev_priv->vbt.edp_rate >> 3, max_clock);
>  	}
>  
>  	for (; bpp >= 6*3; bpp -= 2*3) {
>  		mode_rate = intel_dp_link_required(adjusted_mode->crtc_clock,
>  						   bpp);
>  
> -		for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
> -			for (clock = 0; clock <= max_clock; clock++) {
> +		for (lane_count = min_lane_count; lane_count <= max_lane_count; lane_count <<= 1) {
> +			for (clock = min_clock; clock <= max_clock; clock++) {
>  				link_clock = drm_dp_bw_code_to_link_rate(bws[clock]);
>  				link_avail = intel_dp_max_data_rate(link_clock,
>  								    lane_count);
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch