Hello,
I use vanilla kernel-2.6.29.2, it is configured with CONFIG_USB_SUSPEND=y,
but autosuspend is enabled only for host controllers, and not for attached
devices.
Just after plug-in:
$ find /sys -wholename *power/level
/sys/devices/pci0000:00/0000:00:02.0/usb2/power/level
/sys/devices/pci0000:00/0000:00:02.1/usb3/power/level
/sys/devices/pci0000:00/0000:00:02.1/usb3/3-1/power/level
/sys/devices/pci0000:00/0000:00:02.2/usb1/power/level
/sys/devices/pci0000:00/0000:00:02.2/usb1/1-5/power/level
$ find /sys -wholename *power/level | xargs cat
auto
auto
on
auto
on
Of course I can enable autosuspend manually:
# echo auto > /sys/devices/pci0000:00/0000:00:02.1/usb3/3-1/power/level
# echo auto > /sys/devices/pci0000:00/0000:00:02.2/usb1/1-5/power/level
$ find /sys -wholename *power/level | xargs cat
auto
auto
auto
auto
auto
But this should be done every single time after device plug-in. Currently I use
udev for this task, but it looks like an ugly hack. Is there any better way to
handle this? IMO if kernel is configured with USB power saving enabled, it
*should* be enabled by default. Is there any reason to avoid this?
P.S.
Devices in question are:
$ cat /sys/devices/pci0000:00/0000:00:02.{1/usb3/3-1,2/usb1/1-5}/{product,manufacturer}
USB-Serial Controller C
Prolific Technology Inc.
DEF-299A Camera
USB2.0 Camera
but this shouldn't really be a matter...
--
Best regards,
Andrew
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