linux-kernel - Re: [PATCH 6/6] usb: typec: ucsi: pr_swap should check connector

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Message-ID: <aOWoq08H-3F66Ozg@google.com>
Date: Tue, 7 Oct 2025 23:56:27 +0000
From: Benson Leung <bleung@...gle.com>
To: Jameson Thies <jthies@...gle.com>
Cc: heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, dmitry.baryshkov@....qualcomm.com,
	bleung@...omium.org, gregkh@...uxfoundation.org,
	akuchynski@...omium.org, abhishekpandit@...omium.org,
	sebastian.reichel@...labora.com, linux-pm@...r.kernel.org
Subject: Re: [PATCH 6/6] usb: typec: ucsi: pr_swap should check
 connector_status

On Tue, Oct 07, 2025 at 12:00:07AM +0000, Jameson Thies wrote:
> From: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> 
> Power role swaps initiated by the host system doesn't generate
> connection status change notifications.
> 
> From UCSIv3.0 spec, section 6.5.10 Set Power Direction Role:
> 
> The execution of this command might require PPM to initiate a power
> role swap. If the power role swap fails for any reason, the command
> returns, and error and the power direction should remain unchanged.
> Note that if the execution of the command resulted in a successful
> power role swap, it should not result in a connector status change
> notification.
> 
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> Signed-off-by: Jameson Thies <jthies@...gle.com>

Reviewed-by: Benson Leung <bleung@...omium.org>


> ---
>  drivers/usb/typec/ucsi/ucsi.c | 30 +++++++++++++++++++++++++-----
>  1 file changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index 1a7d850b11ea..6e3797d7a144 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1526,20 +1526,40 @@ static int ucsi_pr_swap(struct typec_port *port, enum typec_role role)
>  	if (ret < 0)
>  		goto out_unlock;
>  
> -	mutex_unlock(&con->lock);
> +	command = UCSI_GET_CONNECTOR_STATUS | UCSI_CONNECTOR_NUMBER(con->num);
> +	ret = ucsi_send_command(con->ucsi, command, &con->status, sizeof(con->status));
> +	if (ret < 0)
> +		goto out_unlock;
>  
> -	if (!wait_for_completion_timeout(&con->complete,
> -					 msecs_to_jiffies(UCSI_SWAP_TIMEOUT_MS)))
> -		return -ETIMEDOUT;
> +	cur_role = !!UCSI_CONSTAT(con, PWR_DIR);
>  
> -	mutex_lock(&con->lock);
> +	/* Execution of SET_PDR should not result in connector status
> +	 * notifications. However, some legacy implementations may still defer
> +	 * the actual role swap and return immediately. Thus, check the
> +	 * connector status in case it immediately succeeded or wait for a later
> +	 * connector status change.
> +	 */
> +	if (cur_role != role) {
> +		mutex_unlock(&con->lock);
> +
> +		if (!wait_for_completion_timeout(
> +			    &con->complete,
> +			    msecs_to_jiffies(UCSI_SWAP_TIMEOUT_MS)))
> +			return -ETIMEDOUT;
> +
> +		mutex_lock(&con->lock);
> +	}
>  
>  	/* Something has gone wrong while swapping the role */
>  	if (UCSI_CONSTAT(con, PWR_OPMODE) != UCSI_CONSTAT_PWR_OPMODE_PD) {
>  		ucsi_reset_connector(con, true);
>  		ret = -EPROTO;
> +		goto out_unlock;
>  	}
>  
> +	/* Indicate successful power role swap */
> +	typec_set_pwr_role(con->port, role);
> +
>  out_unlock:
>  	mutex_unlock(&con->lock);
>  
> -- 
> 2.51.0.618.g983fd99d29-goog
> 

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