drm/i915/dp: read more receiver capability bits on hotplug

When a hotplug event is received, we need to check the receiver cap bits
in case they've changed (as they might with a hub or chain config).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index fc51730..a9a5051 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1522,6 +1522,8 @@ intel_dp_link_down(struct intel_dp *intel_dp)
 static void
 intel_dp_check_link_status(struct intel_dp *intel_dp)
 {
+       int ret;
+
        if (!intel_dp->base.base.crtc)
                return;
 
@@ -1530,6 +1532,15 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
                return;
        }
 
+       /* Try to read receiver status if the link appears to be up */
+       ret = intel_dp_aux_native_read(intel_dp,
+                                      0x000, intel_dp->dpcd,
+                                      sizeof (intel_dp->dpcd));
+       if (ret != sizeof(intel_dp->dpcd)) {
+               intel_dp_link_down(intel_dp);
+               return;
+       }
+
        if (!intel_channel_eq_ok(intel_dp)) {
                intel_dp_start_link_train(intel_dp);
                intel_dp_complete_link_train(intel_dp);