On Wed, 8 Aug 2018, Felipe Balbi wrote: > > Hi, > > Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: > > Felipe: > > > > The documentation doesn't state whether a gadget driver's > > ->disconnect() callback will be invoked when usb_gadget_disconnect() > > runs. Probably the UDC drivers' behavior has changed over the years. > > > > In any case, it's likely that various UDC drivers do behave > > differently. My current feeling is that ->disconnect() should be > > invoked only when Vbus turns off, but I can't guarantee that all UDCs > > will do this. > > my feeling is that ->disconnect() should be called everytime we cause > the session to be killed. VBUS Turning off is a guaratee that session is > gone, but so is disconnecting data pullup, which is what > usb_gadget_disconnect() does. Okay. I don't mind either way, so long as it is settled. > > How do you feel about documenting this ambiguity as in the patch below? > > If you think this is okay, I'll submit it formally. > > Perhaps a better approach would be to start auditing all UDCs to make > sure that ->disconnect() is called when pullup is disconnected. Then we > can move ->disconnect() to usb_gadget_disconnect() itself. No? Rather the other way around: Call ->disconnect() from usb_gadget_disconnect() itself, then audit all the UDCs to make sure they don't invoke the callbackup. That's better than adding a callback to the UDCs that are missing it, only then to remove it from all of them later on. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
