It does: the option is available at the top right of the dialog that shows up when you press Ctrl+S while highlighting the drive in question.
Also, confirming that disabling SMART does allow my Western Digital drive to sleep, though I haven't timed how long it takes for that to occur. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to udisks2 in Ubuntu. https://bugs.launchpad.net/bugs/1281588 Title: Disk standby timer is broken Status in “udisks2” package in Ubuntu: Triaged Bug description: gnome-disk-utility's support for the drive standby timer is broken. Instead of issuing the STANDBY command to the drive, it issues the IDLE command. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/udisks2/+bug/1281588/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

