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Message-ID: <aa8db441-766c-4b2f-8062-ec3dd9067789@rowland.harvard.edu>
Date: Wed, 27 Sep 2023 09:38:57 -0400
From: Alan Stern <stern@...land.harvard.edu>
To: Krishna Kurapati <quic_kriskura@...cinc.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Francesco Dolcini <francesco.dolcini@...adex.com>,
Badhri Jagan Sridharan <badhri@...gle.com>,
Michael Grzeschik <m.grzeschik@...gutronix.de>,
Ivan Orlov <ivan.orlov0322@...il.com>,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
quic_ppratap@...cinc.com, quic_wcheng@...cinc.com,
quic_jackp@...cinc.com
Subject: Re: [PATCH v5] usb: gadget: udc: Handle gadget_connect failure
during bind operation
On Wed, Sep 27, 2023 at 01:00:27PM +0530, Krishna Kurapati wrote:
> In the event gadget_connect call (which invokes pullup) fails,
> propagate the error to udc bind operation which in turn sends the
> error to configfs. The userspace can then retry enumeration if
> it chooses to.
>
> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
> ---
> Changes in v5: Addressed proper unlocking of control_lock mutex
Reviewed-by: Alan Stern <stern@...land.harvard.edu>
> drivers/usb/gadget/udc/core.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
> index 7d49d8a0b00c..824fe64e078a 100644
> --- a/drivers/usb/gadget/udc/core.c
> +++ b/drivers/usb/gadget/udc/core.c
> @@ -1125,12 +1125,12 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state);
> /* ------------------------------------------------------------------------- */
>
> /* Acquire connect_lock before calling this function. */
> -static void usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock)
> +static int usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock)
> {
> if (udc->vbus)
> - usb_gadget_connect_locked(udc->gadget);
> + return usb_gadget_connect_locked(udc->gadget);
> else
> - usb_gadget_disconnect_locked(udc->gadget);
> + return usb_gadget_disconnect_locked(udc->gadget);
> }
>
> static void vbus_event_work(struct work_struct *work)
> @@ -1604,12 +1604,23 @@ static int gadget_bind_driver(struct device *dev)
> }
> usb_gadget_enable_async_callbacks(udc);
> udc->allow_connect = true;
> - usb_udc_connect_control_locked(udc);
> + ret = usb_udc_connect_control_locked(udc);
> + if (ret)
> + goto err_connect_control;
> +
> mutex_unlock(&udc->connect_lock);
>
> kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
> return 0;
>
> + err_connect_control:
> + udc->allow_connect = false;
> + usb_gadget_disable_async_callbacks(udc);
> + if (gadget->irq)
> + synchronize_irq(gadget->irq);
> + usb_gadget_udc_stop_locked(udc);
> + mutex_unlock(&udc->connect_lock);
> +
> err_start:
> driver->unbind(udc->gadget);
>
> --
> 2.42.0
>
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