On Thu, 1 May 2014, Dan Williams wrote: > I've been testing this and the pm_request_resume() ends up leaving the > usb device enabled indefinitely. It needs to be paired with a > pm_runtime_autosuspend(), but at that point why not just add a > usb_autoresume_device_async() helper. Why didn't pm_request_resume() result in an autosuspend? I just tested this patch on my system: Index: usb-3.15/drivers/usb/core/sysfs.c =================================================================== --- usb-3.15.orig/drivers/usb/core/sysfs.c +++ usb-3.15/drivers/usb/core/sysfs.c @@ -11,6 +11,7 @@ #include <linux/kernel.h> +#include <linux/pm_runtime.h> #include <linux/string.h> #include <linux/usb.h> #include <linux/usb/quirks.h> @@ -55,6 +56,8 @@ static ssize_t bMaxPower_show(struct dev if (actconfig) rc = sprintf(buf, "%dmA\n", usb_get_max_power(udev, actconfig)); usb_unlock_device(udev); + dev_info(dev, "calling request_resume\n"); + pm_request_resume(dev); return rc; } static DEVICE_ATTR_RO(bMaxPower); With no USB devices plugged into bus 1 and the root hub suspended, doing "cat /sys/bus/usb/devices/usb1/bMaxPower" caused the root hub to resume and suspend again shortly thereafter. 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
