linux-kernel - Re: usb: typec: ucsi: Clear EVENT_PENDING bit if ucsi_send

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Date:   Mon, 11 Sep 2023 15:49:47 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Prashanth K <quic_prashk@...cinc.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        "# 5 . 16" <stable@...r.kernel.org>
Subject: Re: usb: typec: ucsi: Clear EVENT_PENDING bit if ucsi_send_command
 fails

On Mon, Sep 11, 2023 at 02:34:15PM +0530, Prashanth K wrote:
> Currently if ucsi_send_command() fails, then we bail out without
> clearing EVENT_PENDING flag. So when the next connector change
> event comes, ucsi_connector_change() won't queue the con->work,
> because of which none of the new events will be processed.
> 
> Fix this by clearing EVENT_PENDING flag if ucsi_send_command()
> fails.
> 
> Cc: <stable@...r.kernel.org> # 5.16
> Fixes: 512df95b9432 ("usb: typec: ucsi: Better fix for missing unplug events issue")
> Signed-off-by: Prashanth K <quic_prashk@...cinc.com>
> ---
>  drivers/usb/typec/ucsi/ucsi.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index c6dfe3d..509c67c 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -884,6 +884,7 @@ static void ucsi_handle_connector_change(struct work_struct *work)
>  	if (ret < 0) {
>  		dev_err(ucsi->dev, "%s: GET_CONNECTOR_STATUS failed (%d)\n",
>  			__func__, ret);
> +		clear_bit(EVENT_PENDING, &con->ucsi->flags);
>  		goto out_unlock;
>  	}

I think it would be better to just move that label (out_unlock) above
the point where clear_bit() is already called instead of separately
calling it like that. That way the Connector Change Event will
also get acknowledged.

If this really can happen, then I think it would be good to also
schedule a task for ucsi_check_connection():

        if (ret < 0) {
                dev_err(ucsi->dev, "%s: GET_CONNECTOR_STATUS failed (%d)\n",
                        __func__, ret);
+               ucsi_partner_task(con, ucsi_check_connection, 1, HZ);
                goto out_unlock;
        }

thanks,

-- 
heikki