Possible regression between 4.9 and 4.13

[Mason]

Hello,

The driver for my system's PCIe host bridge landed recently
(in 4.13) but it was developed on 4.9

I tested the PCIe host bridge by plugging a 4-port USB3 adapter
into the PCIe slot (system at rest) and plugging an USB3 Flash
drive into the USB3 adapter (at run-time).

On 4.9, the setup works (almost perfectly, see below).
On 4.13, once I unplug the Flash drive, the controller port
remains unresponsive.


On 4.9, I said *almost* perfectly, because the pcieport driver
does report a few non-fatal errors when I unplug:

[  193.838504] usb 2-2: new SuperSpeed USB device number 2 using xhci_hcd
[  193.878081] usb-storage 2-2:1.0: USB Mass Storage device detected
[  193.884547] scsi host0: usb-storage 2-2:1.0
[  194.907936] scsi 0:0:0:0: Direct-Access     Kingston DataTraveler 3.0      PQ: 0 ANSI: 6
[  194.920296] sd 0:0:0:0: [sda] 15109516 512-byte logical blocks: (7.74 GB/7.20 GiB)
[  194.928666] sd 0:0:0:0: [sda] Write Protect is off
[  194.933755] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[  194.946074]  sda: sda1
[  194.953608] sd 0:0:0:0: [sda] Attached SCSI removable disk

[  208.930260] pcieport 0000:00:00.0: AER: Uncorrected (Non-Fatal) error received: id=0000
[  208.938342] pcieport 0000:00:00.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, id=0000(Requester ID)
[  208.950163] pcieport 0000:00:00.0:   device [1105:0024] error status/mask=00004000/00000000
[  208.958577] pcieport 0000:00:00.0:    [14] Completion Timeout     (First)
[  208.965432] pcieport 0000:00:00.0: AER: Device recovery failed
[  209.663733] xhci_hcd 0000:01:00.0: Cannot set link state.
[  209.669194] usb usb2-port2: cannot disable (err = -32)
[  209.674376] usb 2-2: USB disconnect, device number 2
[  209.680481] pcieport 0000:00:00.0: AER: Uncorrected (Non-Fatal) error received: id=0000
[  209.688689] pcieport 0000:00:00.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, id=0000(Requester ID)
[  209.700555] pcieport 0000:00:00.0:   device [1105:0024] error status/mask=00004000/00000000
[  209.708978] pcieport 0000:00:00.0:    [14] Completion Timeout     (First)
[  209.715845] pcieport 0000:00:00.0: AER: Device recovery failed
[  209.721722] pcieport 0000:00:00.0: AER: Uncorrected (Non-Fatal) error received: id=0000
[  209.729785] pcieport 0000:00:00.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, id=0000(Requester ID)
[  209.741602] pcieport 0000:00:00.0:   device [1105:0024] error status/mask=00004000/00000000
[  209.750027] pcieport 0000:00:00.0:    [14] Completion Timeout     (First)
[  209.756866] pcieport 0000:00:00.0: AER: Device recovery failed

After that, I can still plug the drive into the same port.

But on 4.13, I get

[   27.330378] usb 2-2: new SuperSpeed USB device number 2 using xhci_hcd
[   27.369383] usb-storage 2-2:1.0: USB Mass Storage device detected
[   27.375840] scsi host0: usb-storage 2-2:1.0
[   28.403035] scsi 0:0:0:0: Direct-Access     Kingston DataTraveler 3.0      PQ: 0 ANSI: 6
[   28.413326] sd 0:0:0:0: [sda] 15109516 512-byte logical blocks: (7.74 GB/7.20 GiB)
[   28.423653] sd 0:0:0:0: [sda] Write Protect is off
[   28.429139] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[   28.441529]  sda: sda1
[   28.449431] sd 0:0:0:0: [sda] Attached SCSI removable disk

[   90.592134] xhci_hcd 0000:01:00.0: xHCI host controller not responding, assume dead
[   90.599857] xhci_hcd 0000:01:00.0: HC died; cleaning up
[   90.605336] usb 2-2: USB disconnect, device number 2
[   90.630414] udevd[955]: inotify_add_watch(6, /dev/sda, 10) failed: No such file or directory

Trying to replug into the same port = nothing happens
(Linux did say "assume dead")

Any idea what could have changed between 4.9 and 4.13 ?

Regards.