Re: [PATCH v2 2/2] usb: typec: altmodes/displayport: do not enter mode if port is the UFP

[Heikki Krogerus]

On Tue, Sep 23, 2025 at 06:16:08PM +0000, RD Babiera wrote:
> Nothing currently stops the DisplayPort Alt Mode driver from sending
> Enter Mode if the port is the Data Device. Utilize
> typec_altmode_get_data_role to prevent mode entry.
> 
> Signed-off-by: RD Babiera <rdbabiera@xxxxxxxxxx>

Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/altmodes/displayport.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index 1dcb77faf85d..8d111ad3b71b 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -758,7 +758,9 @@ int dp_altmode_probe(struct typec_altmode *alt)
>  	struct fwnode_handle *fwnode;
>  	struct dp_altmode *dp;
>  
> -	/* FIXME: Port can only be DFP_U. */
> +	/* Port can only be DFP_U. */
> +	if (typec_altmode_get_data_role(alt) != TYPEC_HOST)
> +		return -EPROTO;
>  
>  	/* Make sure we have compatible pin configurations */
>  	if (!(DP_CAP_PIN_ASSIGN_DFP_D(port->vdo) &
> -- 
> 2.51.0.534.gc79095c0ca-goog

-- 
heikki