Should usb_gadget_disconnect() call driver's ->disconnect?
Hi,
Quoted 10 lines · Alan Stern
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.
Quoted 2 lines
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?