Re: [PATCH] usb: hub: move resume delay at the head of all USB access functions

[Alan Stern]

On Mon, 23 Dec 2019, AceLan Kao wrote:

> > > you'll encounter the below errors sometime.
> > > After the issue happens, have to re-plug the USB cable to recover.
> > >
> > > [ 837.483573] hub 2-3:1.0: hub_ext_port_status failed (err = -71)
> > > [ 837.490889] hub 2-3:1.0: hub_ext_port_status failed (err = -71)
> > > [ 837.506780] usb 2-3-port4: cannot disable (err = -71)
> >
> > You need to do a better job of figuring out why these errors occur.  It
> > is not connected to the resume delay; there must be a different reason.
> > Hint: This is the sort of error you would expect to see if the kernel
> > tried to resume a device while its parent hub was still suspended.
> Once this error shows, the USB port doesn't work until re-plug the cable.
> I have no idea what else I can do to this, do you have any idea that I
> could try?
> Thanks.

Maybe you can collect a usbmon trace showing what happens when the 
error occurs.  There's probably something going on that you aren't 
aware of.

Alan Stern