Re: [PATCH v2] usb: hub: use shorter 120ms post resume hold for SS root hubs

[Mathias Nyman]

On 9/3/26 14:29, Lovekesh Solanki wrote:
> Holding a USB3 hub PM runtime reference for 200ms at hub resume triggers
> an AMD platform issue.  Users running Android adb report crashes after
> adb has been polling and waking up the USB subsystem once a second for
> some time.  Vendors are working on a solution.  Disabling USB runtime PM
> is one way to prevent this issue, but it is also proven that reducing the
> hold time to 120ms in resume also mitigates it.  See Link for more
> details.
>
> Reducing the hold time to 120ms for the USB3 roothub is in itself a valid
> change and optimization, as the current 200ms is excessive: a root hub
> has no upstream suspended hub whose wake propagation needs to be
> accounted for, but still need some time for USB3 link training to
> complete.
>
> Keep the 200ms hold for external hubs that commit 8f5b7e2bec1c
> ("usb: hub: fix detection of high tier USB3 devices behind suspended
> hubs") is intended for.
>
> Reported-by: Mathieu Fluhr <mathieu.fluhr@xxxxxxxxx>
> Link: https://lore.kernel.org/all/CAPyJwA_D9qw0T72f8zwM1yKjP+To=maVANbcdsWM7yRmbBxYvw@xxxxxxxxxxxxxx/
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 8f5b7e2bec1c ("usb: hub: fix detection of high tier USB3 devices behind suspended hubs")
> Signed-off-by: Lovekesh Solanki <lovekeshsolanki00@xxxxxxxxx>

Acked-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>