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

[Jani Nikula]

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 at intel.com>
---
 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