Am Montag, 16. August 2010, 16:04:52 schrieb Alan Stern: > On Sun, 15 Aug 2010, Oliver Neukum wrote: > > > Yes, that is true. But where is the connection to open/close? > > When the device file is closed, the sd driver tells the device to > synchronize its cache. While the file is open, we don't know whether > or not the cache has been written back. While this may not matter for > flash drives, it does matter for other kinds -- and I wanted the > initial patch to work with a broad range of devices. Don't we sync cache in sd when suspend() is called? > At the moment it appears that we have three possible criteria for when > to power-down a SCSI drive: > > When the device file is closed; > > When the device file is closed and no medium is present That is a degenerate case > (or maybe just when no medium is present); This is not. > After a user-specified idle timeout. > > The second is basically a degenerate subcase of the first, to be used > with things like card readers that report a media change whenever they > power back up. Do you have any additional suggestions before I post > something on linux-scsi? My concern is that I doubt that cases 1 and 3 are distinct. Now as you can surely suspend an open device without medium provided you reawaken it for a command, I don't see the case for tracking open/close. Regards Oliver -- 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
