[PATCH v1 1/3] dt-bindings: display: synopsys,dw-hdmi: add ignore-rxsense

[PATCH v1 1/3] dt-bindings: display: synopsys,dw-hdmi: add ignore-rxsense

[Ian Ray]

Add a new property to ignore RXSENSE during hotplug events.

Fixes: da09daf88108 ("drm: bridge: dw_hdmi: only trigger hotplug event on link change")
Signed-off-by: Ian Ray <ian.ray@gehealthcare.com>
---
 .../bindings/display/bridge/synopsys,dw-hdmi.yaml         | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml b/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml
index 33481381cccc..0f6e4dabe11d 100644
--- a/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml
@@ -61,6 +61,14 @@ properties:
   interrupts:
     maxItems: 1
 
+  ignore-rxsense:
+    type: boolean
+    description:
+      Determine the connector status from the HPD signal alone and ignore RX
+      sense. Set this on boards where a downstream device (for example an HDMI
+      to DP converter) keeps the TMDS lines permanently loaded, so that RX
+      sense is always asserted and can never signal a disconnect.
+
 additionalProperties: true
 
 ...
-- 
2.47.3

[PATCH v1 3/3] ARM: dts: imx: bx50v3: ignore HDMI rxsense

[Ian Ray]

HDMI is converted to DP in the B450, B650, and B850 boards; as such the
rxsense must be ignored for hotplug detect to work.

Signed-off-by: Ian Ray <ian.ray@gehealthcare.com>
---
 arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi b/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi
index 2c8d2ab8cda1..8e129b1bdbbf 100644
--- a/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi
+++ b/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi
@@ -174,6 +174,11 @@ m25_eeprom: eeprom@0 {
 	};
 };
 
+&hdmi {
+	/* converted to DP using STDP2600 */
+	ignore-rxsense;
+};
+
 &i2c1 {
 	pinctrl-names = "default", "gpio";
 	pinctrl-1 = <&pinctrl_i2c1_gpio>;
-- 
2.47.3

Re: [PATCH v1 3/3] ARM: dts: imx: bx50v3: ignore HDMI rxsense

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The `ignore-rxsense` property masks the `RX_SENSE` bit too late in the interrupt handler, causing the PHY to remain powered on and failing to invalidate the CEC physical address on cable unplug.
--

commit c6070e883038c9a4fefc26add73992b31945db06
Author: Ian Ray <ian.ray@gehealthcare.com>

ARM: dts: imx: bx50v3: ignore HDMI rxsense
    
HDMI is converted to DP in the B450, B650, and B850 boards; as such the
rxsense must be ignored for hotplug detect to work.

> diff --git a/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi b/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi
> index 2c8d2ab8cda13..8e129b1bdbbfc 100644
> --- a/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi
> +++ b/arch/arm/boot/dts/nxp/imx/imx6q-bx50v3.dtsi
> @@ -174,6 +174,11 @@ m25_eeprom: eeprom@0 {
>  	};
>  };
>  
> +&hdmi {
> +	/* converted to DP using STDP2600 */
> +	ignore-rxsense;
> +};

[Severity: High]
Does adding this property expose a logic error in dw_hdmi_irq()?

Looking at drivers/gpu/drm/bridge/synopsys/dw-hdmi.c, the masking for
ignore_rxsense is applied after the critical state machine functions have
already evaluated the raw phy_stat:

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c:dw_hdmi_irq() {
...
		dw_hdmi_setup_rx_sense(hdmi,
				       phy_stat & HDMI_PHY_HPD,
				       phy_stat & HDMI_PHY_RX_SENSE);

		if ((phy_stat & (HDMI_PHY_RX_SENSE | HDMI_PHY_HPD)) == 0) {
			mutex_lock(&hdmi->cec_notifier_mutex);
...
		if (hdmi->ignore_rxsense)
			phy_stat &= ~HDMI_PHY_RX_SENSE;
...
}

Because RX_SENSE is permanently asserted on boards with this property,
phy_stat & HDMI_PHY_RX_SENSE evaluates to true during an unplug event.

Since dw_hdmi_setup_rx_sense() is called before the mask is applied, it will
receive rx_sense = true, which skips clearing hdmi->rxsense and leaves the
PHY powered on indefinitely.

Additionally, the CEC invalidation condition evaluates to false, failing to
invalidate the CEC physical address when the cable is unplugged.

Should the masking of HDMI_PHY_RX_SENSE occur earlier in the interrupt
handler, before evaluating phy_stat for these state machine operations?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260902130117.2731-1-ian.ray@gehealthcare.com?part=3

Re: [PATCH v1 1/3] dt-bindings: display: synopsys,dw-hdmi: add ignore-rxsense

[Conor Dooley]

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On Wed, Sep 02, 2026 at 04:01:13PM +0300, Ian Ray wrote:
> Add a new property to ignore RXSENSE during hotplug events.
> 
> Fixes: da09daf88108 ("drm: bridge: dw_hdmi: only trigger hotplug event on link change")
> Signed-off-by: Ian Ray <ian.ray@gehealthcare.com>
> ---
>  .../bindings/display/bridge/synopsys,dw-hdmi.yaml         | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml b/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml
> index 33481381cccc..0f6e4dabe11d 100644
> --- a/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml
> @@ -61,6 +61,14 @@ properties:
>    interrupts:
>      maxItems: 1
>  
> +  ignore-rxsense:
> +    type: boolean
> +    description:
> +      Determine the connector status from the HPD signal alone and ignore RX
> +      sense. Set this on boards where a downstream device (for example an HDMI
> +      to DP converter) keeps the TMDS lines permanently loaded, so that RX
> +      sense is always asserted and can never signal a disconnect.

I'm not very familiar at all with these kinds of devices, but this seems
like something pretty generic that not only this IP would need. Are
there other examples of this?

Additionally, you're missing a vendor prefix in the case that this does
remain limited to this one device.

pw-bot: changes-requested

Thanks,
Conor.

> +
>  additionalProperties: true
>  
>  ...
> -- 
> 2.47.3
> 

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