On Tue, Nov 08, 2022 at 02:02:19AM +0000, Thinh Nguyen wrote:
> Hi,
>
> On Sun, Nov 06, 2022, Janne Grunau wrote:
> > The change breaks device tree based platforms with PHY device and use
> > usb-role-switch instead of an extcon switch. extcon_find_edev_by_node()
> > will return EPROBE_DEFER if it can not find a device so probing without
> > an extcon device will be deferred indefinitely. Fix this by
> > explicitly checking for usb-role-switch.
> > At least the out-of-tree USB3 support on Apple silicon based platforms
> > using dwc3 with tipd USB Type-C and PD controller is affected by this
> > issue.
> >
> > Fixes: d182c2e1bc92 ("usb: dwc3: Don't switch OTG -> peripheral if extcon is present")
> > Cc: stable@xxxxxxxxxx
> > Signed-off-by: Janne Grunau <j@xxxxxxxxxx>
> > ---
> > drivers/usb/dwc3/core.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index c0e7c76dc5c8..1f348bc867c2 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1710,6 +1710,16 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
> > if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
> > return extcon_get_extcon_dev(name);
> >
> > + /*
> > + * Check explicitly if "usb-role-switch" is used since
> > + * extcon_find_edev_by_node() can not be used to check the absence of
>
> can not -> can't or cannot
"can not" is fine.
>
> > + * an extcon device. In the absence of an device it will always return
>
> "a" device,
Not an issue.
> > + * EPROBE_DEFER.
> > + */
> > + if (IS_ENABLED(CONFIG_USB_ROLE_SWITCH) &&
> > + device_property_read_bool(dev, "usb-role-switch"))
> > + return NULL;
> > +
> > /*
> > * Try to get an extcon device from the USB PHY controller's "port"
> > * node. Check if it has the "port" node first, to avoid printing the
> > --
> > 2.37.3
> >
>
> Looks like the "port" node check from c824c73a5e08 ("usb: dwc3: drd:
> Avoid error when extcon is missing") did not account for this platform
> setup.
>
> This looks fine to me. Should we cleanup the incomplete check and stale
> comment right after this too (as a separate patch)?
Is this a Reviewed-by: ?
thanks,
greg k-h
