[PATCH v4 3/3] drm/bridge: megachips: remove bridge when irq request fails

[PATCH v4 3/3] drm/bridge: megachips: remove bridge when irq request fails

[Osama Abdelkader]

If devm_request_threaded_irq() fails after drm_bridge_add(), remove the
bridge before returning.

Keep drm_bridge_add() rather than devm_drm_bridge_add(): registration is
tied to the STDP4028 device while ge_b850v3_register() may complete from
either I2C probe; devm would not unwind the bridge if the other client's
probe fails.

Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
Fixes: fcfa0ddc18ed ("drm/bridge: Drivers for megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)")
Cc: stable@vger.kernel.org
---
v4: update Fixes tag
v3: add Fixes and Cc tags
v2: IRQ failure path only (explicit drm_bridge_remove)
---
 .../drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
index c9e6505cbd88..2d02cc69f237 100644
--- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
+++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
@@ -251,7 +251,6 @@ static void ge_b850v3_lvds_remove(void)
 		goto out;
 
 	drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
-
 	ge_b850v3_lvds_ptr = NULL;
 out:
 	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
@@ -261,6 +260,7 @@ static int ge_b850v3_register(void)
 {
 	struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c;
 	struct device *dev = &stdp4028_i2c->dev;
+	int ret;
 
 	/* drm bridge initialization */
 	ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |
@@ -277,11 +277,15 @@ static int ge_b850v3_register(void)
 	if (!stdp4028_i2c->irq)
 		return 0;
 
-	return devm_request_threaded_irq(&stdp4028_i2c->dev,
-			stdp4028_i2c->irq, NULL,
-			ge_b850v3_lvds_irq_handler,
-			IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
-			"ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
+	ret = devm_request_threaded_irq(&stdp4028_i2c->dev,
+					stdp4028_i2c->irq, NULL,
+					ge_b850v3_lvds_irq_handler,
+					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+					"ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
+	if (ret)
+		drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
+
+	return ret;
 }
 
 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c)
-- 
2.43.0

Re: [PATCH v4 3/3] drm/bridge: megachips: remove bridge when irq request fails

[Luca Ceresoli]

On Thu Apr 30, 2026 at 9:56 PM CEST, Osama Abdelkader wrote:
> If devm_request_threaded_irq() fails after drm_bridge_add(), remove the
> bridge before returning.
>
> Keep drm_bridge_add() rather than devm_drm_bridge_add(): registration is
> tied to the STDP4028 device while ge_b850v3_register() may complete from
> either I2C probe; devm would not unwind the bridge if the other client's
> probe fails.

I had a hard time in getting what you mean, until I noticed the global
(ugh) ge_b850v3_lvds_ptr and the two "Only register after both bridges are
probed" checks. Pretty hacky, but definitely for the sake of the fix you're
introducing your patch will be OK.

> Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
> Fixes: fcfa0ddc18ed ("drm/bridge: Drivers for megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)")
> Cc: stable@vger.kernel.org

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com