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 56071a2076
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>
This commit is contained in:
Jani Nikula 2014-09-09 11:25:13 +03:00 committed by Daniel Vetter
parent f8d8a672f9
commit 344c5bbcb7

View File

@ -1068,23 +1068,15 @@ intel_dp_compute_config(struct intel_encoder *encoder,
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) {