GNOME Bugzilla – Bug 759864
disk standby time out setting is ignored after a suspend/resume cycle...
Last modified: 2016-03-05 01:13:49 UTC
If you set a standby timeout for your disks with gdu, then this will not work after you suspend and resume your computer. Otherwise (after a fresh boot for instance) everything works perfectly. I have found many other bug reports from other distros regarding this bug as well. My distro is gentoo but I think it is irrelevant. I have 3.18.3.1 built against and running with udisks 2.1.4.
It's not really a problem of gnome-disks since it's only the GUI. Long-time udisks2 issue: https://bugs.freedesktop.org/show_bug.cgi?id=92479
OK, thanks for pointing this out.