On Tue, Sep 12, 2023 at 04:37:47PM +0530, Prashanth K wrote:
>
>
> On 11-09-23 06:19 pm, Heikki Krogerus wrote:
> > 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@xxxxxxxxxxxxxxx> # 5.16
> > > Fixes: 512df95b9432 ("usb: typec: ucsi: Better fix for missing unplug events issue")
> > > Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
> > > ---
> > > 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.
> Do we really need to ACK in this case since we didn't process the current
> connector change event
You won't get the next event before the first one was ACK'd, right?
> >
> > 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,
> >
> Retrying is a good idea, but ucsi_check_connection() doesn't have the full
> functionality compared to handle_connector_change. I guess
> ucsi_check_connection() will send a set_role, but won't handle the
> connector_change scenarios happening due to PR/DR swap, which will lead to
> deadlocks (due to wait_for_completion). This is just an example. So its
> better to bail out and process the next events, because the failure here is
> from the glink layer.
Fair enough.
--
heikki
