drm/i915/dp: Check for AUXCH error before checking for success

This is paranoid, but I am entirely willing to believe the hardware
could come up with a condition where I get a status with both the 'done'
and 'receive error' bits set.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -426,6 +426,10 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
 			   DP_AUX_CH_CTL_DONE |
 			   DP_AUX_CH_CTL_TIME_OUT_ERROR |
 			   DP_AUX_CH_CTL_RECEIVE_ERROR);
+
+		if (status & (DP_AUX_CH_CTL_TIME_OUT_ERROR |
+			      DP_AUX_CH_CTL_RECEIVE_ERROR))
+			continue;
 		if (status & DP_AUX_CH_CTL_DONE)
 			break;
 	}