On Sun, Apr 04, 2010 at 06:28:59PM -0400, Alan Stern wrote:
> On Sun, 4 Apr 2010, Dominik Brodowski wrote:
>
> > Alan, Oliver,
> >
> > On Sun, Apr 04, 2010 at 07:42:33PM +0200, Dominik Brodowski wrote:
> > > Oliver,
> > >
> > > Unfortunately, autosuspend of btusb does not seem to work on my notebook
> > > with 2.6.34-rc3:
> >
> > Debugging this a bit further (that's what long train rides are for):
> >
> > 1) btusb_open() gets called, which contains a pair of
> > usb_autopm_get_interface(), usb_autopm_put_interface() calls. It
> > sets needs_remote_wakeup = 1; in between there are two calls to
> > usb_mark_last_busy().
> >
> > 2) There follow a few usb_mark_last_busy() calls.
> >
> > 3) Then, btusb_close() gets called, which again contains a pair of
> > usb_autopm_{get,put}_interface() calls. Once btusb_close() returns,
> > atomic_read(&intf->dev.power.usage_count) returns 0.
> >
> > This means that after startup, this usage_count is 0. Nonetheless,
> > btusb's suspend callback is never called, despite the following settings:
> >
> > # cat /sys/module/usbcore/parameters/autosuspend
> > 2
> >
> > # cat /sys/bus/usb/devices/7-1/power/level
> > auto
>
> The logic for autosuspend is more or less contained in
> drivers/usb/core/driver.c:autosuspend_check(). It gets called from
> usb_autopm_do_interface(), called by usb_autopm_put_interface().
> (That's in 2.6.33; in 2.6.34-rc the arrangement is a little different
> but not too much.) If you add some debugging statements to those
> routines you ought to be able to figure out what's going on.
usb_autopm_put_interface() gets called, the bus rt_idle function is called,
which does nothing on interfaces:
[ 470.809499] btusb 7-1:1.0: calling bus rt_idle
[ 470.809507] btusb 7-1:1.0: usb_autopm_put_interface: cnt 0 -> 0
rt_suspending usb 7-1 is never attempted, probably because it thinks
children are busy. Setting the interface's ignore_children to true doesn't
help. The device tree looks like this:
.
|-- 7-0:1.0
| |-- driver -> ../../../../../bus/usb/drivers/hub
| |-- ep_81
|-- 7-1
| |-- 7-1:1.0
| | |-- bluetooth
| | | `-- hci0
| | | |-- device -> ../../../7-1:1.0
| | | |-- rfkill2
| | | | |-- device -> ../../hci0
| | | | `-- subsystem -> ../../../../../../../../../class/rfkill
| | | `-- subsystem -> ../../../../../../../../class/bluetooth
| | |-- driver -> ../../../../../../bus/usb/drivers/btusb
| | |-- ep_02
| | |-- ep_81
| | |-- ep_82
| |-- 7-1:1.1
| | |-- driver -> ../../../../../../bus/usb/drivers/btusb
| | |-- ep_03
| | |-- ep_83
| | |-- power
| |-- 7-1:1.2
| | |-- ep_04
| | |-- ep_84
| | |-- power
| |-- 7-1:1.3
| | |-- power
| |-- driver -> ../../../../../bus/usb/drivers/usb
| |-- ep_00
|-- ep_00
Any ideas?
Best,
Dominik
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