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 <[email protected]>
---
Changes in v5: Addressed proper unlocking of control_lock mutex
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
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 <[email protected]>
> ---
> Changes in v5: Addressed proper unlocking of control_lock mutex
Reviewed-by: Alan Stern <[email protected]>
> 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
>
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.
Will this break userspace that is not expecting error codes to be
returned? What userspace code will now be modified to handle this?
Where is that work happening?
thanks,
greg k-h
On 9/27/2023 1:46 PM, Greg Kroah-Hartman wrote:
> 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.
>
> Will this break userspace that is not expecting error codes to be
> returned? What userspace code will now be modified to handle this?
> Where is that work happening?
>
> thanks,
Hi Greg,
This only handles cases where the pullup failed but the error code
wasn't returned to configfs_udc_store approrpiately. In userspace when
we do the following:
echo "UDC NAME" > /usb_gadget/<>/UDC
in the issue I was facing, the core soft reset was failing and we return
-110 from dwc3/core.c to udc's bind_to_driver call, but it is not
checked any where today and we return 0 to udc_store in configfs. The
userspace assumes the UDC write went through (and enum happened) but it
actually doesn't. If we propagate the -ETIMEDOUT coming from dwc3-core
all the way to configfs_udc_store, it will reach userspace as well
indicating that the echo command was not successful which then the user
can choose to retry or not. On Android devices, I saw userspace retry
happening when we propagate dwc3-core error to userspace. So nothing in
userspace breaks. It can stay as it but this time, the echo in userspace
will fail if pullup fails for some reason.
Regards,
Krishna,