On Wed, 18 Sep 2013, Marc MERLIN wrote: > Howdy, > > I have a T530 with a built in webcam that uses the uvcvideo driver. > Kernel 3.10.6, but the problem has been there for many kernel versions. > > From time to time (not always) it shows up at the top of powertop with > an unexplained high power use while I'm not using the camera. > Powertop says autosuspend is active: > Note that tunables says: > Good Autosuspend for USB device Integrated Camera [Chicony Electronics Co., Ltd.] > > Unloading uvcvideo makes no difference. However if I never load uvcvideo > and never use the camera after booting the laptop, then the device > doesn't use any power. > This is better than nothing, but not very desirable since I do use the > camera from time to google for video conferencing. > > Here's the module info > gandalfthegreat:/sys/bus/usb/drivers/uvcvideo# l > total 0 > drwxr-xr-x 2 root root 0 Sep 18 17:48 ./ > drwxr-xr-x 12 root root 0 Sep 17 15:10 ../ > lrwxrwxrwx 1 root root 0 Sep 18 21:30 3-1.6:1.0 -> ../../../../devices/pci0000:00/0000:00:1a.0/usb3/3-1/3-1.6/3-1.6:1.0/ > lrwxrwxrwx 1 root root 0 Sep 18 21:30 3-1.6:1.1 -> ../../../../devices/pci0000:00/0000:00:1a.0/usb3/3-1/3-1.6/3-1.6:1.1/ > --w------- 1 root root 4096 Sep 18 21:30 bind > lrwxrwxrwx 1 root root 0 Sep 18 21:30 module -> ../../../../module/uvcvideo/ > -rw-r--r-- 1 root root 4096 Sep 18 21:30 new_id > -rw-r--r-- 1 root root 4096 Sep 18 21:30 remove_id > --w------- 1 root root 4096 Sep 18 17:48 uevent > --w------- 1 root root 4096 Sep 18 21:30 unbind > > gandalfthegreat:/sys/bus/usb/devices/3-1.6/power# grep . * > active_duration:61227648 > async:enabled > autosuspend:2 > autosuspend_delay_ms:2000 > connected_duration:66830880 > control:auto > level:auto > persist:1 > runtime_active_kids:0 > runtime_active_time:18870052 > runtime_enabled:enabled > runtime_status:active > runtime_suspended_time:5324088 > runtime_usage:0 This all looks correct. > Any ideas? You might get more information from a kernel with CONFIG_USB_DEBUG enabled. Especially if you add #define VERBOSE_DEBUG to drivers/usb/core/driver.c before the first #include line. Alan Stern -- 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
