drm/i915: Use dp_detect_common in hotplug helper function

This uses the common dpcd reading routine, i915_dp_detect_common,
instead of open-coding a call to intel_dp_aux_native_read. Besides
reducing duplicated code, this also gains the read retries which
may be necessary when a cable is first plugged back in and the link
needs to be retrained.

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

1 files changed, 19 insertions, 20 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index dcc7ae6d4141..45db8106ab12 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1567,6 +1567,20 @@ intel_dp_link_down(struct intel_dp *intel_dp)
         POSTING_READ(intel_dp->output_reg);
 }
 
+static enum drm_connector_status
+i915_dp_detect_common(struct intel_dp *intel_dp)
+{
+        enum drm_connector_status status = connector_status_disconnected;
+
+        if (intel_dp_aux_native_read_retry(intel_dp, 0x000, intel_dp->dpcd,
+                                           sizeof (intel_dp->dpcd)) &&
+            (intel_dp->dpcd[DP_DPCD_REV] != 0)) {
+                status = connector_status_connected;
+        }
+
+        return status;
+}
+
 /*
  * According to DP spec
  * 5.1.2:
@@ -1579,45 +1593,30 @@ 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;
 
+        /* Try to read receiver status if the link appears to be up */
         if (!intel_dp_get_link_status(intel_dp)) {
                 intel_dp_link_down(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)) {
+        /* Now read the DPCD to see if it's actually running */
+        if (i915_dp_detect_common(intel_dp) != connector_status_connected) {
                 intel_dp_link_down(intel_dp);
                 return;
         }
 
         if (!intel_channel_eq_ok(intel_dp)) {
+                DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
+                              drm_get_encoder_name(&intel_dp->base.base));
                 intel_dp_start_link_train(intel_dp);
                 intel_dp_complete_link_train(intel_dp);
         }
 }
 
 static enum drm_connector_status
-i915_dp_detect_common(struct intel_dp *intel_dp)
-{
-        enum drm_connector_status status = connector_status_disconnected;
-
-        if (intel_dp_aux_native_read_retry(intel_dp, 0x000, intel_dp->dpcd,
-                                           sizeof (intel_dp->dpcd)) &&
-            (intel_dp->dpcd[DP_DPCD_REV] != 0))
-                status = connector_status_connected;
-
-        return status;
-}
-
-static enum drm_connector_status
 ironlake_dp_detect(struct intel_dp *intel_dp)
 {
         enum drm_connector_status status;