On Thu, Aug 2, 2018 at 7:08 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Thu, 2 Aug 2018, Muni Sekhar wrote: > >> [ Please keep me in CC as I'm not subscribed to the list] >> >> >> Hello All, >> >> >> I’ve an Ubuntu 16.04 LTS PC with 4.4.0-124-generic kernel version. >> >> I want to test the dynamic suspend for the below mentioned connected >> USB device. >> >> Bus 003 Device 028: ID 0cf3:e300 Atheros Communications, Inc. >> >> >> First I’d like to know the required configuration(kernel built) of the >> kernel for supporting the dynamic suspend for USB. >> >> My kernel had been built with the below mentioned configuration: >> CONFIG_SUSPEND=y >> CONFIG_HIBERNATION=y >> CONFIG_PM=y >> >> Any other kernel configuration required for supporting the dynamic suspend? > > No. > >> How can I suspend a particular USB device? > > You have to do something like: > > echo auto >/sys/bus/usb/devices/.../power/control > > where the "..." is filled in with the appropriate name for the > particular device. There are some programs, like powertop, which will > do this for you automatically. Thank you Alan for this information. I wrote 'auto' to power/control, but still device not going to suspend mode(power/runtime_status is 'active'). Any other factors needs to be considered? Here is the my log: # cat /sys/bus/usb/devices/1-1.3/idVendor 0cf3 # cat /sys/bus/usb/devices/1-1.3/idProduct e300 # cat /sys/bus/usb/devices/1-1.3/power/control on # cat /sys/bus/usb/devices/1-1.3/power/runtime_status active # cat /sys/bus/usb/devices/1-1.3/power/runtime_suspended_time 0 # echo auto > /sys/bus/usb/devices/1-1.3/power/control # cat /sys/bus/usb/devices/1-1.3/power/control auto # cat /sys/bus/usb/devices/1-1.3/power/runtime_status active > >> How do I verify whether the device went to suspended mode or >> not(without connecting the USB analyzer)? > > cat /sys/bus/usb/devices/.../power/runtime_status > > will tell you whether or not the device is currently suspended. > > Alan Stern > -- Thanks, Sekhar -- 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
