On Sat, 7 Sep 2013, Aaron Lu wrote: > >>> Note that due to ODD will be polled every 2 seconds, > >> > >> Since the device will be polled every 2 seconds > >> > >>> for suspend to > >>> actually happen, the autosuspend_delay can not be set to more than 2 > >>> seconds or the polling interval has to be increased. > >> > >> Is this true? What about event driven devices? Supposing a distro has > >> a different interval. > >> > >> How about > >> > >> If your Distribution polls the device, the autosuspend interval cannot > >> be set to longer than the polling interval otherwise the device will > >> never suspend. > > > > The default polling done by the kernel uses 2-second intervals. Of > > course, distributions and users can change this or disable it entirely. > > What about: > Note that due to the device will be polled by kernel at a constant > interval specified at /sys/module/block/parameters/events_dfl_poll_msecs, > the default value is 2 seconds, the autosuspend delay cannot be set to > longer than the polling interval otherwise the device will never suspend. Well, I wouldn't say "cannot" -- people can set the delay to whatever they want. Just: If the autosuspend delay is set longer than the polling interval then the device will never suspend. Also, the actual polling interval is controlled by /sys/block/sdX/events_poll_msec. The file you mentioned merely contains the default polling interval used for new devices. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
