Re: [RFT PATCH 0/2] xhci: clean up endpoint rings after disconnect detect

[Dennis Wissel <dennis@dsine.de>]

I tested v7.3 (CachyOS 7.3.0-4) + both patches with the Keychron M5
(3434:d068) plugged in at boot, two boots, with
xhci_hcd.dyndbg=+p usbhid.dyndbg=+p usbcore.dyndbg=+p.

In both boots the M5 drops off at the first control transfers after
Set Configuration, and ep0 on the disconnected port now goes through
the new path:

[    3.536042] xhci_hcd 0000:00:14.0: Not resetting ep 2 slot 1 after disconnect
[    3.536404] xhci_hcd 0000:00:14.0: Transfer error for slot 1 ep 0 on endpoint
[    3.536447] xhci_hcd 0000:00:14.0: TRB error 4, halted endpoint index = 0
[    3.536487] xhci_hcd 0000:00:14.0: Hard-reset ep 0, slot 1

followed by Set TR Deq, the URB given back with -71 and further URBs
refused with "Can't queue urb, port disconnect or link inactive".

Boot 1: no interface was bound before the drop, so all four fail
within 2 ms, as on v7.2. hub_wq handles the disconnect at 5.31 s and
the M5 comes back as a new device at 5.72 s, all four interfaces bound
at 5.94 s.

Boot 2: interfaces 0 and 1 were bound, so usbhid requested a reset:

[    4.539124] usbhid 1-1:1.1: resetting device
[    4.771324] usb usb1-port1: not enabled, trying reset again...
[    5.023262] usb 1-1: reset full-speed USB device number 2 using xhci_hcd
[    5.135351] xhci_hcd 0000:00:14.0: Can't reset device (slot ID 1) in default state
[    5.135498] xhci_hcd 0000:00:14.0: Successful setup address command
[    5.148062] xhci_hcd 0000:00:14.0: Successful Endpoint Configure command

The device is resuscitated in place on the same slot and ep0 works
again after the reset. Mouse and keyboard work after boot.

In neither boot are there "not part of TD" messages or any stall (with
1f36cc9fa949 alone, hub_wq stalled from 4.97 s to 16 s). initrd takes
2.9-3.0 s, the same as v7.2.11.

One observation, probably not xhci related: in boot 2, interfaces 2
and 3 failed their probe before the reset ("reading report descriptor
failed") and stay unbound after the in-place reset, until the mouse is
replugged. On v7.2 the device was re-enumerated instead, so all four
interfaces ended up bound.

Tested-by: Dennis Wissel <dennis@dsine.de>

Full logs are available if needed.

Regards, Dennis