On 09/06/2013 11:56 PM, Alan Stern wrote: > On Fri, 6 Sep 2013, James Bottomley wrote: > >>> layer runtime PM. Accordingly, the SCSI bus layer runtime PM callback is >>> simplified as all SCSI devices that implement runtime PM are now request >>> based. >> >> OK, let's now try for a descriptive changelog. All SCSI devices >> (including sr) are "request based". I think what you mean is "all SCSI >> devices which implement runtime PM have an exposed block device"? > > Actually Aaron means "All SCSI drivers implementing runtime PM now use > the block layer's request-based mechanism." Exactly, thanks for the clarification Alan. I'll update changlog using the above words in v3. > >>> 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. Thanks, Aaron -- 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
