Quoting Kuogee Hsieh (2021-04-14 14:02:34)

Link status is different from display connected status in the case of something like an Apple dongle where the type-c plug can be connected, and therefore the link is connected, but no sink is connected until an HDMI cable is plugged into the dongle. The sink_count of DPCD of dongle will increase to 1 once an HDMI cable is plugged into the dongle so that display connected status will become true. This checking also apply at pm_resume.

Fixes: 94e58e2d06e3 ("drm/msm/dp: reset dp controller only at boot up and pm_resume") Reported-by: Stephen Boyd swboyd@chromium.org Reviewed-by: Stephen Boyd swboyd@chromium.org Tested-by: Stephen Boyd swboyd@chromium.org Signed-off-by: Kuogee Hsieh khsieh@codeaurora.org

---

Can you please thread your emailed patches? I see them all as toplevel messages in my inbox :(

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 5a39da6..0ba71c7 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -586,10 +586,8 @@ static int dp_connect_pending_timeout(struct dp_display_private *dp, u32 data) mutex_lock(&dp->event_mutex);

    state = dp->hpd_state;

•   if (state == ST_CONNECT_PENDING) {
  

•           dp_display_enable(dp, 0);
  

•   if (state == ST_CONNECT_PENDING)
            dp->hpd_state = ST_CONNECTED;
  

•   }
  
    mutex_unlock(&dp->event_mutex);
  
  

@@ -669,10 +667,8 @@ static int dp_disconnect_pending_timeout(struct dp_display_private *dp, u32 data mutex_lock(&dp->event_mutex);

    state =  dp->hpd_state;

•   if (state == ST_DISCONNECT_PENDING) {
  

•           dp_display_disable(dp, 0);
  

•   if (state == ST_DISCONNECT_PENDING)
            dp->hpd_state = ST_DISCONNECTED;
  

•   }
  
    mutex_unlock(&dp->event_mutex);
  
  

@@ -1272,7 +1268,12 @@ static int dp_pm_resume(struct device *dev)

    status = dp_catalog_link_is_connected(dp->catalog);

•   if (status)
  

•   /*
  

•    * can not declared display is connected unless
  

•    * HDMI cable is plugged in and sink_count of
  

•    * dongle become 1
  

•    */
  

•   if (status && dp->link->sink_count)
            dp->dp_display.is_connected = true;
    else
            dp->dp_display.is_connected = false;
  

With this patch applied things still go wrong for me sometimes. I can connect the apple dongle and then disconnect the apple dongle, instead of connect and disconnect the HDMI cable, and sometimes the external display doesn't come on. I'm still investigating but just wanted to let you know.