Re: [PATCH] xhci: check device notification type before forwarding wake event

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 9/29/26 14:28, xy521521@gmail.com wrote:
> From: Hongyu Xie <xiehongyu1@kylinos.cn>
> 
> The xHCI driver programs the Device Notification Control register to
> only enable the Function Wake device notification (N1), so any Device
> Notification Event TRB received is expected to be a function wake
> notification. handle_device_notification() does however not check the
> Notification Type field of the event (xHCI 1.2 section 6.4.2.7, DW0
> bits 7:4), and forwards every device notification event as a function
> wake.
> 
> A host controller that delivers an unexpected notification type (e.g.
> due to broken firmware or emulation) would trigger a spurious wake
> notification on the parent hub.
> 
> Parse the notification type and drop events other than Function Wake
> with a warning, mirroring the slot ID validation in the same function.
> 
> DEV_NOTE_FWAKE is the DNCTRL register bit for notification type 1
> (N1), while the event TRB carries the notification type value itself,
> so add a separate DEV_NOTE_TYPE_FWAKE constant for the comparison.
> 
> Signed-off-by: Hongyu Xie <xiehongyu1@kylinos.cn>

Added, but changed warning to a debug message

Thanks
Mathias