Re: [PATCH v1] usb: gadget: udc: core: Offload usb_udc_vbus_handler processing

[Alan Stern]

On Wed, May 17, 2023 at 11:59:55AM +0000, Badhri Jagan Sridharan wrote:
> chipidea udc calls usb_udc_vbus_handler from udc_start gadget
> ops causing a deadlock. Avoid this by offloading usb_udc_vbus_handler
> processing.

Surely that is the wrong approach.

The real problem here is that usb_udc_vbus_handler() gets called from 
within a udc_start routine.  But this is totally unnecessary, because 
the UDC core will call usb_udc_connect_control_locked() itself, later on 
during gadget_bind_driver().

So a proper solution would be simply to remove the unnecessary
usb_udc_vbus_handler() call from the chipidea driver (and similarly for 
the max3420_udc driver).

Similar changes may be needed in these drivers' udc_stop routines.

Alan Stern