drm/msm/hdmi: Fix wrong CTRL1 register used in writing info frames

[PATCH] drm/msm/hdmi: Fix wrong CTRL1 register used in writing info frames

Posted by Krzysztof Kozlowski 3 weeks, 5 days ago

Commit 384d2b03d0a1 ("drm/msm/hdmi: make use of the drm_connector_hdmi
framework") changed the unconditional register writes in few places to
updates: read, apply mask, write.  The new code reads
REG_HDMI_INFOFRAME_CTRL1 register, applies fields/mask for
HDMI_INFOFRAME_CTRL0 register and finally writes to
HDMI_INFOFRAME_CTRL0.  This difference between CTRL1 and CTRL0 looks
unintended and may result in wrong data being written to HDMI bridge
registers.

Cc: <stable@vger.kernel.org>
Fixes: 384d2b03d0a1 ("drm/msm/hdmi: make use of the drm_connector_hdmi framework")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
index 3c407e275ce5..a9eb6489c520 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
@@ -153,7 +153,7 @@ static int msm_hdmi_bridge_write_avi_infoframe(struct drm_bridge *bridge,
 	for (i = 0; i < ARRAY_SIZE(buf); i++)
 		hdmi_write(hdmi, REG_HDMI_AVI_INFO(i), buf[i]);
 
-	val = hdmi_read(hdmi, REG_HDMI_INFOFRAME_CTRL1);
+	val = hdmi_read(hdmi, REG_HDMI_INFOFRAME_CTRL0);
 	val |= HDMI_INFOFRAME_CTRL0_AVI_SEND |
 		HDMI_INFOFRAME_CTRL0_AVI_CONT;
 	hdmi_write(hdmi, REG_HDMI_INFOFRAME_CTRL0, val);
@@ -193,7 +193,7 @@ static int msm_hdmi_bridge_write_audio_infoframe(struct drm_bridge *bridge,
 		   buffer[9] << 16 |
 		   buffer[10] << 24);
 
-	val = hdmi_read(hdmi, REG_HDMI_INFOFRAME_CTRL1);
+	val = hdmi_read(hdmi, REG_HDMI_INFOFRAME_CTRL0);
 	val |= HDMI_INFOFRAME_CTRL0_AUDIO_INFO_SEND |
 		HDMI_INFOFRAME_CTRL0_AUDIO_INFO_CONT |
 		HDMI_INFOFRAME_CTRL0_AUDIO_INFO_SOURCE |
-- 
2.51.0

Re: [PATCH] drm/msm/hdmi: Fix wrong CTRL1 register used in writing info frames

Posted by Dmitry Baryshkov 1 week, 3 days ago

On Wed, 11 Mar 2026 20:16:21 +0100, Krzysztof Kozlowski wrote:
> Commit 384d2b03d0a1 ("drm/msm/hdmi: make use of the drm_connector_hdmi
> framework") changed the unconditional register writes in few places to
> updates: read, apply mask, write.  The new code reads
> REG_HDMI_INFOFRAME_CTRL1 register, applies fields/mask for
> HDMI_INFOFRAME_CTRL0 register and finally writes to
> HDMI_INFOFRAME_CTRL0.  This difference between CTRL1 and CTRL0 looks
> unintended and may result in wrong data being written to HDMI bridge
> registers.
> 
> [...]

Applied to msm-next, thanks!

[1/1] drm/msm/hdmi: Fix wrong CTRL1 register used in writing info frames
      https://gitlab.freedesktop.org/lumag/msm/-/commit/8c6c93b7db42

Best regards,
-- 
With best wishes
Dmitry

Re: [PATCH] drm/msm/hdmi: Fix wrong CTRL1 register used in writing info frames

Posted by Dmitry Baryshkov 3 weeks, 5 days ago

On Wed, Mar 11, 2026 at 08:16:21PM +0100, Krzysztof Kozlowski wrote:
> Commit 384d2b03d0a1 ("drm/msm/hdmi: make use of the drm_connector_hdmi
> framework") changed the unconditional register writes in few places to
> updates: read, apply mask, write.  The new code reads
> REG_HDMI_INFOFRAME_CTRL1 register, applies fields/mask for
> HDMI_INFOFRAME_CTRL0 register and finally writes to
> HDMI_INFOFRAME_CTRL0.  This difference between CTRL1 and CTRL0 looks
> unintended and may result in wrong data being written to HDMI bridge
> registers.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: 384d2b03d0a1 ("drm/msm/hdmi: make use of the drm_connector_hdmi framework")
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry