Re: [REGRESSION] Sino Wealth 258a:002a keyboard enters stuck shift state on USB disconnect

[Michal Pecio <michal.pecio@gmail.com>]

On Fri, 5 Jun 2026 09:03:42 +0200, Benjamin Tissoires wrote:
> > Trigger captured via udevadm monitor: when a separate Realtek
> > wireless mouse receiver fires unbind -> remove on the USB bus, the
> > Sino Wealth spurious mouse interface reacts to the hub topology
> > change, emits a short report, and the zero-fill behavior causes the
> > keyboard to output "!@#!@#" (Shift held).  
> 
> That is seriously wrong. It's not uncommon for keyboards to expose a
> mouse node when the support "macros" that you can configure in their
> firmware. That allows them to send button events, or even control the
> mouse.
> 
> That being said, if your keyboard reacts to USB events from other
> devices, then there is something seriously wrong in the firmware.
> 
> In any cases, the fix is not to revert the restored behavior, but to
> fix your bogus device.

It's practically impossible for a USB device to respond to disconnection
of another device, but I recall reports of disconnections apparently
causing corruption of other ongoing transactions. These should complete
with -EPIPE, -EPROTO or similar status then. Possibly the kernel or the
device doesn't handle things rigth.

Perhaps a packet trace from usbmon or Wireshark would help understand
what's going on.

> > Physically unplugging and replugging the
> > keyboard does not clear this state; a system reboot is required to
> > restore normal functionality.

When I disconnect a keyboard while holding the SHIFT key, it turns off.
Is there more to this bug than just failing to ignore bogus reports? 

Regards,
Michal