Phillip Susi <phill@xxxxxxxxxxxx> writes: > I noticed though, that when entering system suspend, a disk that has > already been runtime suspended is resumed only to immediately be > suspended again before the system suspend. That shouldn't happen should > it? It seems that it is /sys/power/sync_on_suspend. The problem went away when I unmounted the disk, or I could make the disk wake up by running sync. I thought that it used to be that as long as you mounted an ext4 filesystem with -o relatime, it wouldn't keep dirtying the cache as long as you weren't actually writing to the filesystem. Either I'm misremembering something, or this is no longer the case. Also if there are dirty pages in the cache, I thought the default was for them to be written out after 5 seconds, which would keep the disk awake, rather than waiting until system suspend to sync. I guess I could mount the filesystem readonly. It's probably not a good idea to disable sync_on_suspend for the whole system.
