Re: RTW88 USB Wi-Fi Adapter (8822BU) Disconnects and Fails with USB Write Errors - Status -71 & -110

Re: RTW88 USB Wi-Fi Adapter (8822BU) Disconnects and Fails with USB Write Errors - Status -71 & -110

[Michal Pecio]

Adding linux-usb.

On Thu, 16 Oct 2025 21:32:42 +0000, Samuil wrote:
> My TP-Link Archer T4U (AC1300) Wi-FI adapter has not been working
> properly. When I first boot the system, the device is perfectly
> operational. However, after a few minutes it disconnects. In GNOME
> the whole WiFi GUI is bugged after that: It shows that I am still
> connected but I can't turn off the connection or do anything. `iwctl
> station list` also runs indefinitely without ever showing info. It
> seems like iwd and NetworkManager are blocked by the RTW88 driver.
> When I try to turn off my PC in this state, the driver error blocks
> my OS from entirely shutting down until I unplug the WiFi adapter.

Hi,

So you just join a network (or is this step not necessary?), wait a
moment and it fails? Does it happen every time on every boot?

I have one RTL8822BU (0bda:b812) and it seems to be working fine for
over 10 minutes now. I will leave it running 'ping' overnight.

> Kernel version: 6.17.3 (latest stable)
> 
> Most recent kernel version which did not have the bug: 6.11.*

Any chance you could narrow this more? Perhaps your distribution
has old kernel packages for 6.14 or others versions in the middle?

> The Journal shows following error message during boot:
> ```
> Okt 16 22:10:05 batcomputer kernel: rtw88_8822bu 1-4:1.0: write register 0xc4 failed with -71
> Okt 16 22:10:05 batcomputer kernel: usbcore: registered new interface driver rtw88_8822bu
> Okt 16 22:10:06 batcomputer kernel: usb 2-4: new SuperSpeed USB device number 2 using xhci_hcd

I see it too, but maybe it's just the switch to USB 3 mode?

> When my Internet cuts off, these messages pop up:
> ```
> Okt 16 22:11:55 batcomputer kernel: rtw88_8822bu 2-4:1.0: firmware failed to leave lps state
> Okt 16 22:12:04 batcomputer kernel: xhci_hcd 0000:02:00.0: WARN Set TR Deq Ptr cmd failed due to incorrect slot or ep state.

This shouldn't be here, never a good sign.
May we know what 'lspci -nn' says about this 0000:02:00.0 controller?

Could you boot again, run (the first line needs root)

echo 'module xhci_hcd +p' >/proc/dynamic_debug/control
dmesg -W >somefile

wait until it fails again and attach the resulting 'somefile'?

> Okt 16 22:19:04 batcomputer kernel: xhci_hcd 0000:02:00.0: Event dma 0x0000000105a9e110 for ep 0 status 4 not part of TD at 000000011fd2bd30 - 000000011fd2bd50
> Okt 16 22:19:04 batcomputer kernel: xhci_hcd 0000:02:00.0: Event dma 0x0000000105a9e110 for ep 0 status 4 not part of TD at 000000011fd2bd90 - 000000011fd2bdb0

Yep, definitely xHCI screwup.
Starting to suspect that an AMD chipset may be involved?

Regards,
Michal

RTW88 USB Wi-Fi Adapter (8822BU) Disconnects and Fails with USB Write Errors - Status -71 & -110

[Samuil]

On Friday, October 17th, 2025 at 12:48 AM, Ping-Ke Shih <pkshih@realtek.com> wrote:
> Is it possible to bisect culprit? Since there are 100+ commits since v6.11.

Hey,

With "most recent bugless version" I meant that the bug occurred when I switched to v6.12 from v6.11 and that the issue hasn't been patched since. However, I've now found a workaround though it's not optimal: Setting `rtw88_usb.switch_usb_mode=n` to prevent the switch to USB 3 mode fixed all issues. No more disconnects or error messages. I think this was the default behavior before that version.

Thanks for the help!

RTW88 USB Wi-Fi Adapter (8822BU) Disconnects and Fails with USB Write Errors - Status -71 & -110

[Samuil]

Hey,

On Thursday, October 16th, 2025 at 10:59 PM, Michal Pecio <michal.pecio@gmail.com> wrote:
> Does it happen every time on every boot?
The disconnect happens on every boot although rarely the device is able to reconnect again. Usually, however, the adapter just stops working until I reboot again.

> May we know what 'lspci -nn' says about this 0000:02:00.0 controller?
```
02:00.0 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] 400 Series Chipset USB 3.1 xHCI Compliant Host Controller [1022:43d5] (rev 01)
```

> Yep, definitely xHCI screwup.
> Starting to suspect that an AMD chipset may be involved?
My motherboard is the ROG B450-f gaming. I am using the USB 3.0 ports of my PCs case.

As I mentioned in the other message, the issue seems to be with the USB 3 mode as setting `rtw88_usb.switch_usb_mode=n` fixes the issue for me.
Are you using a USB 2 port for the adapter to be working properly without configuration? 

Best regards,
Samuil

Re: RTW88 USB Wi-Fi Adapter (8822BU) Disconnects and Fails with USB Write Errors - Status -71 & -110

[Michal Pecio]

On Fri, 17 Oct 2025 17:25:03 +0000, Samuil wrote:
> > Does it happen every time on every boot?  
> The disconnect happens on every boot although rarely the device is
> able to reconnect again. Usually, however, the adapter just stops
> working until I reboot again.

Well, I had no luck reproducing this on v6.18-rc1.
I left it running overnight with ping traffic ~700KB/s each way.

> > May we know what 'lspci -nn' says about this 0000:02:00.0 controller?  
> 02:00.0 USB controller [0c03]: Advanced Micro Devices, Inc. [AMD] 400 Series Chipset USB 3.1 xHCI Compliant Host Controller [1022:43d5] (rev 01)

Similar to my B350 chipset.

In some stress tests it showed a HW bug which currently isn't being
worked around by xhci_hcd and I think this bug may be responsible for
at least some of the noise you get, namely this sequence with constant
"event dma" but increasing "TD at":

Event dma 0x0000000105a9e110 for ep 0 status 4 not part of TD at 000000011fd2bd30 - 000000011fd2bd50
Event dma 0x0000000105a9e110 for ep 0 status 4 not part of TD at 000000011fd2bd90 - 000000011fd2bdb0  

It's a broken state which rtw88 can't do anything about. The dynamic
debug I asked for may shed some light on how you got into this state.

Whether fixing this would enable rtw88 to continue is unclear, because
everything likely starts with a "Transaction Error" on endpoint 0. That
could either be a one-off error (harmless if xHCI recoveres from it and
rtw88 retries whatever it wanted to do), or the USB device crashes due
to some traffic pattern unique to your network or whatever.

> Are you using a USB 2 port for the adapter to be working properly
> without configuration?

Nope, I made sure to run it SuperSpeed on my buggy AMD chipset.
This is probably unique to your network traffic or hardware (poor
USB link quality? maybe try other ports.)

Still, I would be curious to see this dynamic debug if possible.

Are you able to compile and run a patched kernel?

Regards,
Michal