Re: [PATCH next] usb: usbfs: Add reset_resume for usbfs

[Oliver Neukum]

On 11.07.24 10:43, Hongyu Xie wrote:
> During hibernation, usb_resume_interface will set needs_binding to 1 if
> the usb_driver has no reset_resume implimentation. The USB interface
> will be rebind after usb_resume_complete.
>
> Normally, that's fine. But if a USB interface has a matched kernel
> driver, and a userspace driver or application is using this USB
> interface through usbfs during hibernation, usbfs will be
> detatched with the USB interface after resume. And this USB interface
> will be bind with a kernel driver instead of usbfs.
>
> So add reset_resume to fix this.

The device has lost all settings, yet we continue like nothing
changed. That strikes me as a very bad idea. If a device has undergone
a reset user space has not requested, we need to return an error upon
the next interaction.

I am sorry, but this implementation has some fundamental issues.

	Regards
		Oliver