Re: [PATCH stable 5.4] usb: host: xhci-plat: add wakeup entry at sysfs

[Florian Fainelli]

On 2/1/23 10:16, Greg Kroah-Hartman wrote:
> On Wed, Feb 01, 2023 at 09:44:04AM -0800, Florian Fainelli wrote:
> > From: Peter Chen <peter.chen@xxxxxxx>
> >
> > commit  4bb4fc0dbfa23acab9b762949b91ffd52106fe4b upstream
> >
> > With this change, there will be a wakeup entry at /sys/../power/wakeup,
> > and the user could use this entry to choose whether enable xhci wakeup
> > features (wake up system from suspend) or not.
> >
> > Tested-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> > Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
> > Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
> > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20200918131752.16488-6-mathias.nyman@xxxxxxxxxxxxxxx
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> > ---
> >   drivers/usb/host/xhci-plat.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
>
> Why is this new feature needed on these older kernels?  What does it fix
> that is broken?

It fixes the inability to make the XHCI controller a wake-up device 
since there is no /sys/*/*xhci/power/wakeup sysfs entry to manipulate 
unless this patch is applied.

> And why not just use a newer kernel release if you want to use this
> feature?

Because I maintain multiple version streams so I have always have a way 
to compare an older with a newer kernel and ensure they all behave properly.

This should have been flagged with a Fixes: tag IMHO in the first place.
--
Florian