On Wed, Jan 11, 2012 at 09:01:04PM -0500, Alan Stern wrote: > On Wed, 11 Jan 2012, Sarah Sharp wrote: > > > > No; the USB Mass Storage specs say nothing about remote wakeup and > > > usb-storage doesn't require it. I haven't heard of any mass-storage > > > devices that would send wakeup requests. > > > > Ok, that's what I thought. Some folks were concerned about bad system > > power management they have been seeing, and they were claiming the host > > didn't need to poll an empty CD drive if the USB CD drive advertised > > remote wakeup in its descriptors. Now I can tell them it's simply not > > true. > > Well, it may be true for all I know. But I haven't run across any USB > CD drives like that. And the spec doesn't say anything about it. > > Besides, what's usb-storage going to do if a CD drive does send a > wakeup request? usb-storage doesn't initiate any SCSI commands on its > own. All that will happen is the autosuspend timer will expire and the > drive will be suspended again. > > (In addition to all that, the SCSI CD driver currently doesn't support > autosuspend. So we can't autosuspend USB CD drives anyway, even if > they aren't being polled.) Oh, so a USB CD drive won't get auto-suspended at all? Sarah Sharp -- 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
