Re: [PATCH 4/4] thunderbolt: prevent pcie tunnel activation/teardown warnings

["mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com>]

Hi,

On Tue, Nov 03, 2026 at 08:33:51AM +0000, Chunfeng Yun (云春峰) wrote:
> On Fri, 2026-10-30 at 09:56 +0100, Mika Westerberg wrote:
> > On Fri, Oct 30, 2026 at 04:25:39PM +0800, Chunfeng Yun wrote:
> > > When usb4 enter sleep mode, echo 1 to authorized of sysfile,
> > > will wakeup usb4 driver, but fail to create pcie tunnel, cause
> > > the warning due to a race condition between switch disconnect
> > 
> > It's router
> will modify it.
> 
> > 
> > > during resume and user authorization
> [  278.831186] usb4_hi NVDA8100:00: 0:1: is unplugged (state: 7),
> retrying...
> [  278.943031] usb4_hi NVDA8100:00: 0:1: failed to reach state
> TB_PORT_UP. Ignoring port...
> [  278.951125] usb4_hi NVDA8100:00: 0:1: lost during suspend,
> disconnecting
> [  278.957819] usb4_hi NVDA8100:00: 0:4 <-> 1:16 (USB3): deactivating
> [  278.964794] usb4_hi NVDA8100:00: deactivating USB3 Down path from
> 0:4 to 1:16
> [  278.972737] usb4_hi NVDA8100:00: deactivating USB3 Up path from 1:16
> to 0:4
> [  278.980504] usb4_hi NVDA8100:00: 0: TMU: mode change off -> bi-
> directional, HiFi requested
> [  278.991265] usb4_hi NVDA8100:00: 0: TMU: mode set to: bi-
> directional, HiFi
> [  278.999511] usb4_hi NVDA8100:00: 0:1: total credits changed 66 -> 66
> [  279.006408] usb4_hi NVDA8100:00: 1: link width set to symmetric,
> dual lanes
> [  279.013763] usb4_hi NVDA8100:00: 0:7 <-> 1:9 (PCI): activating
> [  279.019587] usb4_hi NVDA8100:00: activating PCIe Down path from 0:7
> to 1:9
> [  279.026468] usb4_hi NVDA8100:00: 1:1: Writing hop 1
> [  279.031335] usb4_hi NVDA8100:00: 1:1:  In HopID: 8 => Out port: 9
> Out HopID: 8
> [  279.038546] usb4_hi NVDA8100:00: 1:1:   Weight: 1 Priority: 3
> Credits: 32 Drop: 0 PM: 0
> [  279.046536] usb4_hi NVDA8100:00: 1:1:    Counter enabled: 0 Counter
> index: 2047
> [  279.053834] usb4_hi NVDA8100:00: 1:1:   Flow Control (In/Eg): 1/0
> Shared Buffer (In/Eg): 0/0
> [  279.062259] usb4_hi NVDA8100:00: 1:1:   Unknown1: 0x0 Unknown2: 0x0
> Unknown3: 0x0
> [  279.069730] ------------[ cut here ]------------
> [  279.074335] usb4_hi NVDA8100:00: PCIe Down path activation failed
> [  279.080426] WARNING: CPU: 5 PID: 2433 at
> drivers/thunderbolt/path.c:587 tb_path_activate+0x1a4/0x5b0
> ...
> [  279.220285] Call trace:
> [  279.222722]  tb_path_activate+0x1a4/0x5b0 (P)
> [  279.227068]  tb_tunnel_activate+0x140/0x498
> [  279.231241]  tb_tunnel_pci+0x180/0x490
> [  279.234980]  tb_domain_approve_switch+0x74/0xb0
> [  279.239500]  authorized_store+0x214/0x270
> [  279.243498]  dev_attr_store+0x20/0x70
> ...
> [  279.288888] ---[ end trace 0000000000000000 ]---
> [  279.293497] usb4_hi NVDA8100:00: 0:7 <-> 1:9 (PCI): activation
> failed
> 
> 
> root cause:
> 
> The warning were caused by a race condition between switch disconnect
> during resume and user authorization:
> 
>    1. While the system was in runtime suspend, userspace executed:
> 
>        echo 1 > /sys/bus/thunderbolt/devices/0-1/authorized
>    2. Writing to this sysfs attribute woke up the USB4 controller
> (nhi_runtime_resume).
>    3. During resume, the downstream port 0:1 failed to complete link
> training within the timeout and was declared lost:

Okay we get the warning but the bigger problem here is that why the link
does not come up anymore? Unless you unplugged the router as well.