linux-kernel - [PATCH] drm/bridge/synopsys: dw-hdmi: Fix unwedge crash when no pinctrl entries

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Date:   Mon, 10 Jun 2019 10:52:34 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Sean Paul <seanpaul@...omium.org>
Cc:     linux-rockchip@...ts.infradead.org,
        Erico Nunes <nunes.erico@...il.com>, heiko@...ech.de,
        Douglas Anderson <dianders@...omium.org>,
        David Airlie <airlied@...ux.ie>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Jonas Karlman <jonas@...boo.se>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, Sam Ravnborg <sam@...nborg.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Daniel Vetter <daniel@...ll.ch>
Subject: [PATCH] drm/bridge/synopsys: dw-hdmi: Fix unwedge crash when no pinctrl entries

In commit 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge"
for ddc bus") I stupidly used IS_ERR() to check for whether we have an
"unwedge" pinctrl state even though on most flows through the driver
the unwedge state will just be NULL.

Fix it so that we consistently use NULL for no unwedge state.

Fixes: 50f9495efe30 ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus")
Reported-by: Erico Nunes <nunes.erico@...il.com>
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---

 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index f25e091b93c5..5e4e9408d00f 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -251,7 +251,7 @@ static void dw_hdmi_i2c_init(struct dw_hdmi *hdmi)
 static bool dw_hdmi_i2c_unwedge(struct dw_hdmi *hdmi)
 {
 	/* If no unwedge state then give up */
-	if (IS_ERR(hdmi->unwedge_state))
+	if (!hdmi->unwedge_state)
 		return false;
 
 	dev_info(hdmi->dev, "Attempting to unwedge stuck i2c bus\n");
@@ -2686,11 +2686,13 @@ __dw_hdmi_probe(struct platform_device *pdev,
 			hdmi->default_state =
 				pinctrl_lookup_state(hdmi->pinctrl, "default");
 
-			if (IS_ERR(hdmi->default_state) &&
-			    !IS_ERR(hdmi->unwedge_state)) {
-				dev_warn(dev,
-					 "Unwedge requires default pinctrl\n");
-				hdmi->unwedge_state = ERR_PTR(-ENODEV);
+			if (IS_ERR(hdmi->default_state) ||
+			    IS_ERR(hdmi->unwedge_state)) {
+				if (!IS_ERR(hdmi->unwedge_state))
+					dev_warn(dev,
+						 "Unwedge requires default pinctrl\n");
+				hdmi->default_state = NULL;
+				hdmi->unwedge_state = NULL;
 			}
 		}
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog