Re: xhci: WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.

[Paul Menzel]

Dear Mathias,


Thank you for your quick reply.


Am 04.04.25 um 16:26 schrieb Mathias Nyman:
> On 3.4.2025 21.02, Paul Menzel wrote:

> > Just a heads-up, that connecting an LMP USB-C mini Dock [1] to the 
> > Intel Kaby Lake Dell XPS 13 9360 with
> >
> >      00:14.0 USB controller [0c03]: Intel Corporation Sunrise Point-LP 
> > USB 3.0 xHCI Controller [8086:9d2f] (rev 21)
> >
> > resulted in Linux 6.14.0-12966-ga2cc6ff5ec8f logging the warning and 
> > trace below.
> >
> > ```
> > [   74.898485] usb 4-1.4: reset SuperSpeed USB device number 5 using xhci_hcd
> > [   74.916241] sd 0:0:0:0: [sda] Media removed, stopped polling
> > [   74.916634] sd 0:0:0:0: [sda] Attached SCSI removable disk
> > [   98.803081] PM: suspend entry (deep)
> > [   98.813999] Filesystems sync: 0.010 seconds
> > [   98.819226] Freezing user space processes
> > [  105.534176] xhci_hcd 0000:39:00.0: WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.
> > [  105.606437] usb 4-1.4: reset SuperSpeed USB device number 5 using xhci_hcd
> > [  118.822270] Freezing user space processes failed after 20.003 seconds (2 tasks refusing to freeze, wq_busy=0):
>
> Thanks for the report.
>
> Looks like it's triggered during system suspend.
>
> "The Set TR Deq" command that fails here is queued when
> - endpoint stops to remove cancelled transfers.
> - endpoint resets to clear STALL or other halt due to transfer error.
> - canceling a transfer while endpoint is mid stall or tt clearing.
>
> Looks like there are at least some gaps in verifying endpoint state in 
> endpoint reset handler  before queuing the "Set TR Deq" command, this
> could be a possible reason.
>
> If this case could be reproduces with xhci dynamic debug enabled it 
> would help narrowing down the real cause.
>
> echo 'module xhci_hcd =p' >/sys/kernel/debug/dynamic_debug/control

I haven’t found a way to reliably reproduce it. I’ll try, but it might 
take a while.


Kind regards,

Paul