On Wed, Jan 25, 2017 at 11:01:30AM +0100, Greg KH wrote:
> On Tue, Jan 24, 2017 at 09:18:57AM -0600, Bin Liu wrote:
> > From: Tony Lindgren <tony@xxxxxxxxxxx>
> >
> > Commit 467d5c980709 ("usb: musb: Implement session bit based runtime PM for
> > musb-core") started implementing musb generic runtime PM support by
> > introducing devctl register session bit based state control.
> >
> > This caused a regression where if a USB mass storage device is connected
> > to a USB hub, we can get:
> >
> > usb 1-1: reset high-speed USB device number 2 using musb-hdrc
> > usb 1-1: device descriptor read/64, error -71
> > usb 1-1.1: new high-speed USB device number 4 using musb-hdrc
> >
> > This is because before the USB storage device is connected, musb is
> > in OTG_STATE_A_SUSPEND. And we currently only set need_finish_resume
> > in musb_stage0_irq() and the related code calling finish_resume_work
> > in musb_resume() and musb_runtime_resume() never gets called.
> >
> > To fix the issue, we can call schedule_delayed_work() directly in
> > musb_stage0_irq() to have finish_resume_work run.
> >
> > And we should no longer never get interrupts when when suspended.
> > We have changed musb to no longer need pm_runtime_irqsafe().
> > The need_finish_resume flag was added in commit 9298b4aad37e ("usb:
> > musb: fix device hotplug behind hub") and no longer applies as far
> > as I can tell. So let's just remove the earlier code that no longer
> > is needed.
> >
> > Fixes: 467d5c980709 ("usb: musb: Implement session bit based
> > runtime PM for musb-core")
> > Reported-by: Bin Liu <b-liu@xxxxxx>
> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> > Signed-off-by: Bin Liu <b-liu@xxxxxx>
> > ---
> > drivers/usb/musb/musb_core.c | 15 ++-------------
> > drivers/usb/musb/musb_core.h | 1 -
> > 2 files changed, 2 insertions(+), 14 deletions(-)
>
> As the problem showed up in 4.9, this should go into 4.9-stable, right?
Yes.
>
> thanks,
>
> greg k-h
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