linux-kernel - [PATCH 3/4] drm/bridge: anx7625: Fix NULL pointer crash when using edp-panel

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Message-Id: <20220629160550.433980-4-hsinyi@chromium.org>
Date:   Thu, 30 Jun 2022 00:05:49 +0800
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     Robert Foss <robert.foss@...aro.org>, Xin Ji <xji@...logixsemi.com>
Cc:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Sam Ravnborg <sam@...nborg.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] drm/bridge: anx7625: Fix NULL pointer crash when using edp-panel

Move devm_of_dp_aux_populate_ep_devices() after pm runtime and i2c setup
to avoid NULL pointer crash.

edp-panel probe (generic_edp_panel_probe) calls pm_runtime_get_sync() to
read EDID. At this time, bridge should have pm runtime enabled and i2c
clients ready.

Fixes: adca62ec370c ("drm/bridge: anx7625: Support reading edid through aux channel")
Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 478f5af381c7d..59ddeba33652b 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -2590,14 +2590,6 @@ static int anx7625_i2c_probe(struct i2c_client *client,
 	platform->aux.dev = dev;
 	platform->aux.transfer = anx7625_aux_transfer;
 	drm_dp_aux_init(&platform->aux);
-	devm_of_dp_aux_populate_ep_devices(&platform->aux);
-
-	ret = anx7625_parse_dt(dev, pdata);
-	if (ret) {
-		if (ret != -EPROBE_DEFER)
-			DRM_DEV_ERROR(dev, "fail to parse DT : %d\n", ret);
-		goto free_wq;
-	}
 
 	if (anx7625_register_i2c_dummy_clients(platform, client) != 0) {
 		ret = -ENOMEM;
@@ -2613,6 +2605,15 @@ static int anx7625_i2c_probe(struct i2c_client *client,
 	if (ret)
 		goto free_wq;
 
+	devm_of_dp_aux_populate_ep_devices(&platform->aux);
+
+	ret = anx7625_parse_dt(dev, pdata);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			DRM_DEV_ERROR(dev, "fail to parse DT : %d\n", ret);
+		goto free_wq;
+	}
+
 	if (!platform->pdata.low_power_mode) {
 		anx7625_disable_pd_protocol(platform);
 		pm_runtime_get_sync(dev);
-- 
2.37.0.rc0.161.g10f37bed90-goog