drm/i915/mst: abstract intel_dp_ack_sink_irq_esi()

Smaller functions make the thing easier to read. Debug log failures to
ack.

Note: Looks like we have the retry loop simply because of hysterical
raisins, dating back to the original DP MST enabling. Keep it, though I
have no idea why we have it.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220112110319.1172110-2-jani.nikula@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index e789ecb..a301220 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2821,6 +2821,19 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
                DP_DPRX_ESI_LEN;
 }
 
+static bool intel_dp_ack_sink_irq_esi(struct intel_dp *intel_dp, u8 esi[4])
+{
+       int retry;
+
+       for (retry = 0; retry < 3; retry++) {
+               if (drm_dp_dpcd_write(&intel_dp->aux, DP_SINK_COUNT_ESI + 1,
+                                     &esi[1], 3) == 3)
+                       return true;
+       }
+
+       return false;
+}
+
 bool
 intel_dp_needs_vsc_sdp(const struct intel_crtc_state *crtc_state,
                       const struct drm_connector_state *conn_state)
@@ -3661,7 +3674,6 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
                 */
                u8 esi[DP_DPRX_ESI_LEN+2] = {};
                bool handled;
-               int retry;
 
                if (!intel_dp_get_sink_irq_esi(intel_dp, esi)) {
                        drm_dbg_kms(&i915->drm,
@@ -3686,15 +3698,8 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
                if (!handled)
                        break;
 
-               for (retry = 0; retry < 3; retry++) {
-                       int wret;
-
-                       wret = drm_dp_dpcd_write(&intel_dp->aux,
-                                                DP_SINK_COUNT_ESI+1,
-                                                &esi[1], 3);
-                       if (wret == 3)
-                               break;
-               }
+               if (!intel_dp_ack_sink_irq_esi(intel_dp, esi))
+                       drm_dbg_kms(&i915->drm, "Failed to ack ESI\n");
        }
 
        return link_ok;