Re: USB regression in kernel 6.2.2

[Alan Stern <stern@rowland.harvard.edu>]

On Wed, Mar 15, 2023 at 01:19:16PM +0200, Mathias Nyman wrote:
> On 14.3.2023 16.00, Brian Morrison wrote:
> > On Mon, 13 Mar 2023 12:06:59 +0200
> > Mathias Nyman <mathias.nyman@linux.intel.com> wrote:
> > > 
> > > 
> > > In your v6.2 logs the usb bus numbers are interleaved, in the v6.1
> > > they are not. xhci driver registers two usb buses per host, one
> > > High-Speed and one SuperSpeed.
> > > 
> > > This change could be due to 6.2 commit:
> > > 
> > > 4c2604a9a689 usb: xhci-pci: Set PROBE_PREFER_ASYNCHRONOUS
> > > 
> > > Not sure why it would cause this regression, but worth testing it.
> > 
> > I have now reverted the above commit, it's only the one line in
> > xhci-pci.c and it took a couple of hours to rebuild my kernel rpms which
> > wasn't too bad.
> > 
> > With this change all of my USB devices are present again and the 3
> > /dev/ttyUSB* nodes are all present and usable.
> > 
> 
> Thanks for testing.
> So setting PROBE_PREFER_ASYNCHRONOUS does trigger this issue for Renesas xHCI.
> 
> Was it so that with the devices connected to the Intel host everything worked
> on 6.2 kernel?
> 
> Just to make sure that this is a vendor specific host issue and not generic xhci
> driver issue.
> 
> If we can't quickly figure out the real reason for this then we just have to
> revert that patch.
> 
> > I found this in the linux-usb list archives:
> > 
> > https://www.spinics.net/lists/kernel/msg4569289.html
> > 
> > and the first part of this patch series here:
> > 
> > https://www.spinics.net/lists/kernel/msg4569288.html
> > 
> > Should both of these patches be reverted? I assume so but I don't think
> > I have anything that uses an ehci device to test it.
> > 
> 
> Probably just the xhci one. I haven't heard of any ehci issues.
> 
> Alan (cc) would know better if there are any new odd ehci issues that can
> be traced back to the async probe change.

I haven't heard of any problems with EHCI.

Alan Stern