FAILED: patch "[PATCH] drm/msm/dp: check sink_count before update is_connected" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d9aa6571b28ba0022de1e48801ff03a1854c7ef2 Mon Sep 17 00:00:00 2001
From: Kuogee Hsieh <khsieh@codeaurora.org>
Date: Wed, 21 Apr 2021 16:37:35 -0700
Subject: [PATCH] drm/msm/dp: check sink_count before update is_connected
 status

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.

Changes in v4:
-- none

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>
Fixes: 8ede2ecc3e5e ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
Link: https://lore.kernel.org/r/1619048258-8717-2-git-send-email-khsieh@codeaurora.org
Signed-off-by: Rob Clark <robdclark@chromium.org>

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 5a39da6e1eaf..0ba71c7a8dd4 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;