Am Dienstag, 31. August 2010, 16:43:38 schrieb Alan Stern: > On Tue, 31 Aug 2010, Oliver Neukum wrote: > > > Am Dienstag, 31. August 2010, 16:13:26 schrieb Alan Stern: > > Worse. What happens when the system sleeps and the device does not > > loose power? > > You mean the device remains at full power during system sleep? How > could that happen? Not full power, any power at all. There are three cases a) loss of power -> reset_resume() b) device not buggy -> resume() - no further trouble c) device buggy -> spurious change event We run into (c) if eg. the reader shares power with a wakeup source. > > > Furthermore, other non-buggy devices with removable media might require > > > special treatment. For example, the user might want to have two > > > different autosuspend timeouts: one for media present and one for media > > > not present. If the media-present timeout is set to -1 then it could > > > have the effect of preventing autosuspend. > > > > That is a good plan, as it leaves the problem to someone else. > > It's still not great. It would require putting in all those settings > for each LUN. In a multi-card reader, each card type generally has its > own LUN. Yes. > For those buggy readers, it would be better to have something > which could be implemented as a sysfs attribute in usb-storage. Why usb-storage? Any drive for real rotational media has the same requirement. Waiting for minutes for a suspend without medium is ridiculous, as is spinning down a disk after only two seconds. 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
