drm/i915/dp: return proper DPRX link training result

After DPRX link training, intel_dp_link_train_phy() did not
return the training result properly. If link training failed,
i915 driver would not run into link train fallback function.
And no hotplug uevent would be received by user space application.

Fixes: d3297d093260 ("drm/i915: Switch to LTTPR non-transparent mode link training")
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: William Tseng <william.tseng@intel.com>
Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210706152541.25021-1-shawn.c.lee@intel.com
(cherry picked from commit dab1b47e57e053b2a02c22ead8e7449f79961335)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 053a3c2f726776b5e50aaaf72c40b31630fe5674..508a514c5e37dc241d0b6e3cdd7aab44ab0eb617 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -848,7 +848,7 @@ intel_dp_link_train_all_phys(struct intel_dp *intel_dp,
        }
 
        if (ret)
-               intel_dp_link_train_phy(intel_dp, crtc_state, DP_PHY_DPRX);
+               ret = intel_dp_link_train_phy(intel_dp, crtc_state, DP_PHY_DPRX);
 
        if (intel_dp->set_idle_link_train)
                intel_dp->set_idle_link_train(intel_dp, crtc_state);