Re: Disconnect race in Gadget core

[Felipe Balbi <balbi@kernel.org>]

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Hi,

Peter Chen <peter.chen@kernel.org> writes:
>> I suppose we could do something similar for the composite driver, for 
>> gadgets that don't use configfs.
>
> Originally, I intended to do at composite.c to cover all gadget drivers, but
> I can't find a good way to use usb_composite_dev existing spinlock to do that.
> Since most of users already used configfs, I chose to fix it at configfs directly.
> If we want to fix it for legacy gadget drivers (drivers at drivers/usb/gadget/legacy/).
>
> For .setup & .suspend, we could delay 10ms after usb_gadget_disconnect, ensure
> hardware has triggered related interrupt, and we need to let all UDC drivers to
> add udc->gadget->irq, in that case, the pending threaded interrupt will be handled
> at synchronize_irq at usb_gadget_remove_driver.
> For .disconnect, we could use cdev->config to judge if the first .disconnect
> has run.
>
>> But what about legacy gadgets?  Are 
>> there any still around that don't use either configfs or the composite 
>> framework?
>
> I only find raw_gadget.c that doesn't use composite framework, and it doesn't implement
> many usb_gadget_driver callbacks, eg, .disconnect and .suspend. For .setup, we could
> use above solutions for legacy composite driver.

IIRC the old EHCI debug gadget also fits the bill here.

-- 
balbi

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