drm/i915/edp: use lane count and link rate from DPCD for eDP
eDP panels are generally designed to support only a single clock and
lane configuration.
commit 56071a207602a451f0c46d3dcc8379b59ef576e2
Author: Jani Nikula <jani.nikula@intel.com>
Date: Tue May 6 14:56:52 2014 +0300
drm/i915: use lane count and link rate from VBT as minimums for eDP
should have started using the optimal link parameters for eDP
panels. Turns out a certain other OS uses DPCD instead of VBT, which
means trusting VBT on this may not be so reliable after all. Follow
suit.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81647
Tested-by: Adam Jirasek <libm3l@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79386
Tested-by: Narthana Epa <narthana.epa+freedesktop@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index ab7cd0a..72bf533 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1068,23 +1068,15 @@
bpp = dev_priv->vbt.edp_bpp;
}
- if (IS_BROADWELL(dev)) {
- /* Yes, it's an ugly hack. */
- min_lane_count = max_lane_count;
- DRM_DEBUG_KMS("forcing lane count to max (%u) on BDW\n",
- min_lane_count);
- } else if (dev_priv->vbt.edp_lanes) {
- min_lane_count = min(dev_priv->vbt.edp_lanes,
- max_lane_count);
- DRM_DEBUG_KMS("using min %u lanes per VBT\n",
- min_lane_count);
- }
-
- if (dev_priv->vbt.edp_rate) {
- min_clock = min(dev_priv->vbt.edp_rate >> 3, max_clock);
- DRM_DEBUG_KMS("using min %02x link bw per VBT\n",
- bws[min_clock]);
- }
+ /*
+ * Use the maximum clock and number of lanes the eDP panel
+ * 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.
+ */
+ min_lane_count = max_lane_count;
+ min_clock = max_clock;
}
for (; bpp >= 6*3; bpp -= 2*3) {