linux-kernel - [PATCH 2/2] drm/bridge: it6505: Drop EDID cache on bridge power off

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Message-ID: <20240924035231.1163670-3-treapking@chromium.org>
Date: Tue, 24 Sep 2024 11:51:47 +0800
From: Pin-yen Lin <treapking@...omium.org>
To: Xin Ji <xji@...logixsemi.com>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>
Cc: linux-kernel@...r.kernel.org,
	Sam Ravnborg <sam@...nborg.org>,
	dri-devel@...ts.freedesktop.org,
	Pin-yen Lin <treapking@...omium.org>,
	Douglas Anderson <dianders@...omium.org>
Subject: [PATCH 2/2] drm/bridge: it6505: Drop EDID cache on bridge power off

The bridge might miss the display change events when it's powered off.
This happens when a user changes the external monitor when the system
is suspended and the embedded controller doesn't not wake AP up.

It's also observed that one DP-to-HDMI bridge doesn't work correctly
when there is no EDID read after it is powered on.

Drop the cache to force an EDID read after system resume to fix this.

Fixes: 11feaef69d0c ("drm/bridge: it6505: Add caching for EDID")
Signed-off-by: Pin-yen Lin <treapking@...omium.org>

---

 drivers/gpu/drm/bridge/ite-it6505.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 1e1c06fdf206..bb449efac2f4 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -3101,6 +3101,8 @@ static __maybe_unused int it6505_bridge_suspend(struct device *dev)
 {
 	struct it6505 *it6505 = dev_get_drvdata(dev);
 
+	it6505_remove_edid(it6505);
+
 	return it6505_poweroff(it6505);
 }
 
-- 
2.46.0.792.g87dc391469-goog