On Wed, Jan 25, 2017 at 02:17:11PM +0100, Greg KH wrote:
> On Wed, Jan 25, 2017 at 06:59:47AM -0600, Bin Liu wrote:
> > 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.
>
> Great, please remember to add a cc: stable line for the patch next time
> so I don't have to do it manually...
Ahh, sorry about this. I was thinking about cc stable for a second, but
somehow I thought the 'Fixes:' will do it but now I realized it is
either 'Fixes:' + 'cc stable' or without 'Fixes:' + 'cc stable #<release
tag>'. I guess I was context switching too fast in my work... I will
ensure to double check whenever in doubt in future.
Regards,
-Bin.
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
