On Fri, Jul 12, 2024 at 11:10:57AM +0800, Hongyu Xie wrote: > From: Hongyu Xie <xiehongyu1@xxxxxxxxxx> > > > > On 2024/7/11 16:59, Oliver Neukum wrote: > > > > > > 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. > Sorry I don't understand your concern. > When will "a reset user space has not requested" happen if there is a > reset_resume in usbfs? That's what a reset-resume is: a reset that occurs when the device is resumed, rather than when the driver has requested a reset. Alan Stern > > I am sorry, but this implementation has some fundamental issues. > > > > Regards > > Oliver > > > Regards > Hongyu Xie
