ACK: [SRU][P][PATCH 0/3] Add waiting latency for USB port resume

[Anthony Wong]

On Mon, Aug 11, 2025 at 10:35 PM En-Wei Wu <en-wei.wu at canonical.com> wrote:
>
> BugLink: https://bugs.launchpad.net/bugs/2115478
>
> [ Impact ]
>
> On certain USB3 device topologies, the hub will enter runtime resume
> before the down stream device to wake up. When a device is connect to
> such hub, the hub will enter runtime resume before the device generates
> any activities, making it not able to get detected.
>
> [ Fix ]
>
> Cherry-pick the following commit:
>
> 1. usb: hub: fix detection of high tier USB3 devices behind suspended hubs [1]
>
> and backport the subsequent two commits, which fix an unexpected issue caused
> by the commit above:
>
> 2. usb: hub: Fix flushing and scheduling of delayed work that tunes runtime pm
> 3. usb: hub: Fix flushing of delayed work used for post resume purposes
>
> [ Test ]
>
> 1. Connect SD25TB5/WD25TB5 dock to SUT.
> 2. Connect USB3.0/3.1 sotarge to dock's USB port.
> 3. The USB storage should be recognized.
>
> [ Where problems could occurs ]
>
> This may increase resume latency for deeper USB device
> hierarchy.
>
> [ Additional Information ]
>
> [1]
> https://lore.kernel.org/linux-usb/20250611112441.2267883-1-mathias.nyman@linux.intel.com/
>
> Mathias Nyman (3):
>   usb: hub: fix detection of high tier USB3 devices behind suspended
>     hubs
>   usb: hub: Fix flushing and scheduling of delayed work that tunes
>     runtime pm
>   usb: hub: Fix flushing of delayed work used for post resume purposes
>
>  drivers/usb/core/hub.c | 28 ++++++++++++++++++++++++++++
>  drivers/usb/core/hub.h |  1 +
>  2 files changed, 29 insertions(+)

Acked-by: Anthony Wong <anthony.wong at canonical.com>