On Fri 2014-09-12 10:06:03, Alan Stern wrote: > On Fri, 12 Sep 2014, Petr Mladek wrote: > > > usb_autopm_put_interface() must be called only when usb_autopm_get_interface() > > succeeded before. There was wrong ordering of the goto targets. > > No, you are wrong. The code is correct as it stands. > > > The funny thing is that the names of the goto targets and the related comments > > were correct. > > That's because the whole thing is correct. Go back and read the > comments more carefully -- especially the comment following the "loop:" > label. > > > Signed-off-by: Petr Mladek <pmladek@xxxxxxx> > > --- > > drivers/usb/core/hub.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c > > index d481c99a20d7..6afd79ee3340 100644 > > --- a/drivers/usb/core/hub.c > > +++ b/drivers/usb/core/hub.c > > @@ -5132,12 +5132,12 @@ static void hub_events(void) > > > > loop_autopm: > > /* Balance the usb_autopm_get_interface() above */ > > - usb_autopm_put_interface_no_suspend(intf); > > + usb_autopm_put_interface(intf); > > There's no point to this change. Now this call will decrement the > usage counter and try to suspend -- but the suspend is bound to fail > because the usage counter is still > 0. > > > loop: > > /* Balance the usb_autopm_get_interface_no_resume() in > > * kick_khubd() and allow autosuspend. > > */ > > - usb_autopm_put_interface(intf); > > + usb_autopm_put_interface_no_suspend(intf); > > And now this call will decrement the usage counter down to 0, but won't > try to suspend -- so the hub won't autosuspend at all! Ah, shame on me. It makes perfect sense. I was more focused on the kthread/workqueue conversion and function of the locks. I should have thought more about this as well :-( It means that the patchset "usb: hub: convert khubd into workqueue" needs refreshing. But I will wait for some feedback first. Best Regards, Petr -- 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
