On Thu, 2 Aug 2018, Muni Sekhar wrote: > 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? Yes, there are other factors. They depend on how device's driver is written. I don't know exactly what kind of device you're talking about, what driver it uses, or what the driver's requirements are. Since the vendor is Atheros, I guess it's a wifi card. Perhaps turning wifi off will allow the device to be suspended; you'll probably have to check with the driver's author or maintainer to find out for certain. Alan Stern > 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 -- 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
