diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_dp.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 203198659ab2..09f274419eea 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -3731,9 +3731,16 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp) } - /* Read the eDP Display control capabilities registers */ - if ((intel_dp->dpcd[DP_EDP_CONFIGURATION_CAP] & DP_DPCD_DISPLAY_CONTROL_CAPABLE) && - drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_DPCD_REV, + /* + * Read the eDP display control registers. + * + * Do this independent of DP_DPCD_DISPLAY_CONTROL_CAPABLE bit in + * DP_EDP_CONFIGURATION_CAP, because some buggy displays do not have it + * set, but require eDP 1.4+ detection (e.g. for supported link rates + * method). The display control registers should read zero if they're + * not supported anyway. + */ + if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_DPCD_REV, intel_dp->edp_dpcd, sizeof(intel_dp->edp_dpcd)) == sizeof(intel_dp->edp_dpcd)) DRM_DEBUG_KMS("EDP DPCD : %*ph\n", (int) sizeof(intel_dp->edp_dpcd), |