On May 23, 2012, at 8:25 PM, Alan Stern wrote: > On Wed, 23 May 2012, Pantelis Antoniou wrote: > >>> I don't believe that. Are you sure you haven't mixed up unmounting and >>> ejecting? >>> >> >> I'm using the Finder; I don't fiddle with the command line. >> >> I see an eject icon, I press it, and the disk should umount/eject. > > Is that any different from dragging the disk's icon to the trashcan? > It is the same. >> On the Mac it's all integrated, there's no separate unmount/eject steps. >> >> Speaking of which, I did try to replicate the behavior of the Mac on Linux. >> >> Using udisks to send a detach command I get to see this on the console: >> >>> May 23 17:55:48 beagleboard [ 335.725341] lun0: unload attempt prevented >>> May 23 17:55:48 beagleboard [ 335.725372] gadget: sending command-failure status >>> >> >> And this is the result on the host: >> >>> root@ubuntu:~# sudo udisks --detach /dev/sdb >>> Detach failed: Error detaching: helper exited with exit code 1: Detaching device /dev/sdb >>> USB device: /sys/devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1) >>> SYNCHRONIZE CACHE: OK >>> STOP UNIT: FAILED: No such file or directory >>> >> >> So udisks does send a STOP UNIT command too. Which fails because there was >> a previous command that disallowed media unmounting. > > There is no such command. However there is a command that prevents > media _unloading_. If you unmount all the filesystems on the device > first, unloading will be allowed again. The "eject" command will do > both for you. > All the partitions were unmounted before. The command that prevented media unloading was apparently issued. >> I does sound like we have a code path (STOP UNIT command) that wasn't been >> exercised at all on Linux hosts, but on the Mac it is being exercised with >> unexpected results. > > It _has_ been exercised on Linux hosts. I tested it when it was > originally written. What is the explanation for the sequence above then? Kernel used on the device is mainline 3.4. > >>> For example, what happens when you plug in a regular USB flash memory >>> stick to an OS-X system? Many of them them are not removable. (More >>> accurately, none of them are removable and many of them -- but not all! >>> -- correctly tell the host that they aren't.) Is it then impossible to >>> unmount such a flash drive? >>> >> >> Most of the USB flash memory sticks I've used on the Mac operate perfectly fine. >> >> You click the eject button and they unmount cleanly. There is a strong case to >> be made that a Linux based device that presents a mass memory interface should work >> in the same manner. > > Indeed, the mass-storage gadgets are supposed to present the same > interface and behave in the same manner. > > Alan Stern > Regards -- Pantelis -- 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
