Re: [PATCH v2 04/12] drm/msm/dp: Move link training to atomic_enable()

[Jessica Zhang]

On 8/8/2025 5:45 PM, Dmitry Baryshkov wrote:
On 09/08/2025 03:35, Jessica Zhang wrote:
Currently, the DP link training is being done during HPD. Move
link training to atomic_enable() in accordance with the atomic_enable()
documentation.

Link disabling is already done in atomic_post_disable() (as part of the
dp_ctrl_off_link_stream() helper).

Finally, call the plug/unplug handlers directly in hpd_notify() instead
of queueing them in the event thread so that they aren't preempted by
other events.

This feels like two unrelated changes.

Hi Dmitry,

Ack. Would it make more sense to squash the hpd_notify part with the IRQ 
thread change?

Thanks,

Jessica Zhang



Signed-off-by: Jessica Zhang <jessica.zh...@oss.qualcomm.com>
---
  drivers/gpu/drm/msm/dp/dp_display.c | 15 ++++++++-------
  1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/ 
msm/dp/dp_display.c
index e2556de99894..c849befe58f0 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -427,11 +427,6 @@ static int msm_dp_display_process_hpd_high(struct 
msm_dp_display_private *dp)
      msm_dp_link_psm_config(dp->link, &dp->panel->link_info, false);
      msm_dp_link_reset_phy_params_vx_px(dp->link);
-    rc = msm_dp_ctrl_on_link(dp->ctrl);
-    if (rc) {
-        DRM_ERROR("failed to complete DP link training\n");
-        goto end;
-    }
      msm_dp_add_event(dp, EV_USER_NOTIFICATION, true, 0);
@@ -1680,6 +1675,12 @@ void msm_dp_bridge_atomic_enable(struct 
drm_bridge *drm_bridge,
          force_link_train = true;
      }
+    rc = msm_dp_ctrl_on_link(msm_dp_display->ctrl);
+    if (rc) {
+        DRM_ERROR("Failed link training (rc=%d)\n", rc);
+        dp->connector->state->link_status = DRM_LINK_STATUS_BAD;
+    }
+
      msm_dp_display_enable(msm_dp_display, force_link_train);
      rc = msm_dp_display_post_enable(dp);
@@ -1839,7 +1840,7 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge 
*bridge,
          return;
      if (!msm_dp_display->link_ready && status == 
connector_status_connected)
-        msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
+        msm_dp_hpd_plug_handle(dp, 0);
      else if (msm_dp_display->link_ready && status == 
connector_status_disconnected)
-        msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
+        msm_dp_hpd_unplug_handle(dp, 0);
  }