usb: typec: ucsi: Invert DisplayPort role assignment

[PATCH] usb: typec: ucsi: Invert DisplayPort role assignment

Posted by Andrei Kuchynski 6 days, 15 hours ago

The existing implementation assigned these flags backwards, configuring
the partner's DisplayPort role to match the port's role instead of
complementing it.
This prevents proper configuration during DP altmode activation, often
causing `pin_assignment` to remain 0 in `dp_altmode_configure()` and
resulting in VDM negotiation failures:

    [  583.328246] typec port1.1: VDM 0xff01a150 failed

Additionally, the fix ensures that the `pin_assignment` sysfs attribute 
displays the correct values.

Cc: stable@vger.kernel.org
Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
---
 drivers/usb/typec/ucsi/displayport.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index 8aae80b457d74..669f08013c7ab 100644
--- a/drivers/usb/typec/ucsi/displayport.c
+++ b/drivers/usb/typec/ucsi/displayport.c
@@ -166,12 +166,12 @@ static int ucsi_displayport_status_update(struct ucsi_dp *dp)
 	 * that Multi-function is preferred.
 	 */
 	if (DP_CAP_CAPABILITY(cap) & DP_CAP_UFP_D) {
-		dp->data.status |= DP_STATUS_CON_UFP_D;
+		dp->data.status |= DP_STATUS_CON_DFP_D;
 
 		if (DP_CAP_UFP_D_PIN_ASSIGN(cap) & BIT(DP_PIN_ASSIGN_D))
 			dp->data.status |= DP_STATUS_PREFER_MULTI_FUNC;
 	} else {
-		dp->data.status |= DP_STATUS_CON_DFP_D;
+		dp->data.status |= DP_STATUS_CON_UFP_D;
 
 		if (DP_CAP_DFP_D_PIN_ASSIGN(cap) & BIT(DP_PIN_ASSIGN_D))
 			dp->data.status |= DP_STATUS_PREFER_MULTI_FUNC;
-- 
2.54.0.823.g6e5bcc1fc9-goog

Re: [PATCH] usb: typec: ucsi: Invert DisplayPort role assignment

Posted by Heikki Krogerus 2 days, 16 hours ago

On Mon, Jun 01, 2026 at 02:28:37PM +0000, Andrei Kuchynski wrote:
> The existing implementation assigned these flags backwards, configuring
> the partner's DisplayPort role to match the port's role instead of
> complementing it.
> This prevents proper configuration during DP altmode activation, often
> causing `pin_assignment` to remain 0 in `dp_altmode_configure()` and
> resulting in VDM negotiation failures:
> 
>     [  583.328246] typec port1.1: VDM 0xff01a150 failed
> 
> Additionally, the fix ensures that the `pin_assignment` sysfs attribute 
> displays the correct values.
> 
> Cc: stable@vger.kernel.org
> Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
> Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/ucsi/displayport.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
> index 8aae80b457d74..669f08013c7ab 100644
> --- a/drivers/usb/typec/ucsi/displayport.c
> +++ b/drivers/usb/typec/ucsi/displayport.c
> @@ -166,12 +166,12 @@ static int ucsi_displayport_status_update(struct ucsi_dp *dp)
>  	 * that Multi-function is preferred.
>  	 */
>  	if (DP_CAP_CAPABILITY(cap) & DP_CAP_UFP_D) {
> -		dp->data.status |= DP_STATUS_CON_UFP_D;
> +		dp->data.status |= DP_STATUS_CON_DFP_D;
>  
>  		if (DP_CAP_UFP_D_PIN_ASSIGN(cap) & BIT(DP_PIN_ASSIGN_D))
>  			dp->data.status |= DP_STATUS_PREFER_MULTI_FUNC;
>  	} else {
> -		dp->data.status |= DP_STATUS_CON_DFP_D;
> +		dp->data.status |= DP_STATUS_CON_UFP_D;
>  
>  		if (DP_CAP_DFP_D_PIN_ASSIGN(cap) & BIT(DP_PIN_ASSIGN_D))
>  			dp->data.status |= DP_STATUS_PREFER_MULTI_FUNC;
> -- 
> 2.54.0.823.g6e5bcc1fc9-goog

-- 
heikki