[PATCH v3] drm/mediatek: mtk_hdmi: Fix DDC adapter double put in v2

[PATCH v3] drm/mediatek: mtk_hdmi: Fix DDC adapter double put in v2

[Guangshuo Li]

mtk_hdmi_common_probe() gets the DDC adapter with
of_find_i2c_adapter_by_node() and registers a devm action to release the
adapter device reference with put_device().

The HDMI v2 remove callback also calls i2c_put_adapter() on the same DDC
adapter. This is not paired with of_find_i2c_adapter_by_node(): it drops
the adapter device reference before the devm action drops it again, and
it also puts a module reference that was never taken.

Remove the extra i2c_put_adapter() call and drop the now-empty HDMI v2
remove callback. The common devm action releases the adapter device
reference.

Fixes: 8d0f79886273 ("drm/mediatek: Introduce HDMI/DDC v2 for MT8195/MT8188")
Cc: stable@vger.kernel.org
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
v3:
  - Add Reviewed-by tag from Johan Hovold.
  - No code changes.

v2:
  - Drop the empty remove callback, as suggested by Johan Hovold.
  - Mention that i2c_put_adapter() also drops a module reference that was
    never taken.
  - Fix the Fixes tag.
  - Add Cc stable.

 drivers/gpu/drm/mediatek/mtk_hdmi_v2.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c b/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
index 7bbf463056c9..ffe456238a2b 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
@@ -1499,13 +1499,6 @@ static int mtk_hdmi_v2_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static void mtk_hdmi_v2_remove(struct platform_device *pdev)
-{
-	struct mtk_hdmi *hdmi = platform_get_drvdata(pdev);
-
-	i2c_put_adapter(hdmi->ddc_adpt);
-}
-
 static const struct of_device_id mtk_drm_hdmi_v2_of_ids[] = {
 	{ .compatible = "mediatek,mt8188-hdmi-tx", .data = &mtk_hdmi_conf_mt8188 },
 	{ .compatible = "mediatek,mt8195-hdmi-tx", .data = &mtk_hdmi_conf_mt8195 },
@@ -1515,7 +1508,6 @@ MODULE_DEVICE_TABLE(of, mtk_drm_hdmi_v2_of_ids);
 
 static struct platform_driver mtk_hdmi_v2_driver = {
 	.probe = mtk_hdmi_v2_probe,
-	.remove = mtk_hdmi_v2_remove,
 	.driver = {
 		.name = "mediatek-drm-hdmi-v2",
 		.of_match_table = mtk_drm_hdmi_v2_of_ids,
-- 
2.43.0

Re: [PATCH v3] drm/mediatek: mtk_hdmi: Fix DDC adapter double put in v2

[Johan Hovold]

On Mon, Jul 13, 2026 at 07:29:57PM +0800, Guangshuo Li wrote:
> mtk_hdmi_common_probe() gets the DDC adapter with
> of_find_i2c_adapter_by_node() and registers a devm action to release the
> adapter device reference with put_device().
> 
> The HDMI v2 remove callback also calls i2c_put_adapter() on the same DDC
> adapter. This is not paired with of_find_i2c_adapter_by_node(): it drops
> the adapter device reference before the devm action drops it again, and
> it also puts a module reference that was never taken.
> 
> Remove the extra i2c_put_adapter() call and drop the now-empty HDMI v2
> remove callback. The common devm action releases the adapter device
> reference.
> 
> Fixes: 8d0f79886273 ("drm/mediatek: Introduce HDMI/DDC v2 for MT8195/MT8188")
> Cc: stable@vger.kernel.org
> Reviewed-by: Johan Hovold <johan@kernel.org>
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
> v3:
>   - Add Reviewed-by tag from Johan Hovold.
>   - No code changes.

No need to resend just to add a tag. It will be added when the patch is
applied.

Johan

Re: [PATCH v3] drm/mediatek: mtk_hdmi: Fix DDC adapter double put in v2

[CK Hu (胡俊光)]

On Mon, 2026-07-13 at 19:29 +0800, Guangshuo Li wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> mtk_hdmi_common_probe() gets the DDC adapter with
> of_find_i2c_adapter_by_node() and registers a devm action to release the
> adapter device reference with put_device().
> 
> The HDMI v2 remove callback also calls i2c_put_adapter() on the same DDC
> adapter. This is not paired with of_find_i2c_adapter_by_node(): it drops
> the adapter device reference before the devm action drops it again, and
> it also puts a module reference that was never taken.
> 
> Remove the extra i2c_put_adapter() call and drop the now-empty HDMI v2
> remove callback. The common devm action releases the adapter device
> reference.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Fixes: 8d0f79886273 ("drm/mediatek: Introduce HDMI/DDC v2 for MT8195/MT8188")
> Cc: stable@vger.kernel.org
> Reviewed-by: Johan Hovold <johan@kernel.org>
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
> 

Re: [PATCH v3] drm/mediatek: mtk_hdmi: Fix DDC adapter double put in v2

[Chun-Kuang Hu]

Guangshuo Li <lgs201920130244@gmail.com> 於 2026年7月13日週一 上午11:32寫道：
>
> mtk_hdmi_common_probe() gets the DDC adapter with
> of_find_i2c_adapter_by_node() and registers a devm action to release the
> adapter device reference with put_device().
>
> The HDMI v2 remove callback also calls i2c_put_adapter() on the same DDC
> adapter. This is not paired with of_find_i2c_adapter_by_node(): it drops
> the adapter device reference before the devm action drops it again, and
> it also puts a module reference that was never taken.
>
> Remove the extra i2c_put_adapter() call and drop the now-empty HDMI v2
> remove callback. The common devm action releases the adapter device
> reference.

Applied to mediatek-drm-fixes [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Fixes: 8d0f79886273 ("drm/mediatek: Introduce HDMI/DDC v2 for MT8195/MT8188")
> Cc: stable@vger.kernel.org
> Reviewed-by: Johan Hovold <johan@kernel.org>
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---