linux-kernel - [PATCH 5.10 290/530] drm/probe-helper: Check epoch counter in output_poll

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Date:   Wed, 12 May 2021 16:46:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Daniel Vetter <daniel.vetter@...ll.ch>,
        Noralf Trønnes <noralf@...nnes.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 290/530] drm/probe-helper: Check epoch counter in output_poll_execute()

From: Noralf Trønnes <noralf@...nnes.org>

[ Upstream commit dc659a4e852b591771fc2e5abb60f4455b0cf316 ]

drm_helper_hpd_irq_event() checks the epoch counter to determine
connector status change. This was introduced in
commit 5186421cbfe2 ("drm: Introduce epoch counter to drm_connector").
Do the same for output_poll_execute() so it can detect other changes
beside connection status value changes.

v2:
- Add Fixes tag (Daniel)

Fixes: 5186421cbfe2 ("drm: Introduce epoch counter to drm_connector")
Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
Signed-off-by: Noralf Trønnes <noralf@...nnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210313112545.37527-3-noralf@tronnes.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/drm_probe_helper.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index d6017726cc2a..e5432dcf6999 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -623,6 +623,7 @@ static void output_poll_execute(struct work_struct *work)
 	struct drm_connector_list_iter conn_iter;
 	enum drm_connector_status old_status;
 	bool repoll = false, changed;
+	u64 old_epoch_counter;
 
 	if (!dev->mode_config.poll_enabled)
 		return;
@@ -659,8 +660,9 @@ static void output_poll_execute(struct work_struct *work)
 
 		repoll = true;
 
+		old_epoch_counter = connector->epoch_counter;
 		connector->status = drm_helper_probe_detect(connector, NULL, false);
-		if (old_status != connector->status) {
+		if (old_epoch_counter != connector->epoch_counter) {
 			const char *old, *new;
 
 			/*
@@ -689,6 +691,9 @@ static void output_poll_execute(struct work_struct *work)
 				      connector->base.id,
 				      connector->name,
 				      old, new);
+			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] epoch counter %llu -> %llu\n",
+				      connector->base.id, connector->name,
+				      old_epoch_counter, connector->epoch_counter);
 
 			changed = true;
 		}
-- 
2.30.2