Default How does the CM11 recognize the filesystems on USB devices?

Should the CM11 (crombi-kk) recognize the USB/sd filesystems (by partition type?) by default? I have a usb device with ext4 and fat32 partitions. The android does notice the device is plugged in, but doesn't mount them. I can do it manually from command line, but it seems copying files from partitions get stalled if device sleeps. Perhaps file managers fail to take some wake lock if the fs is not mounted by the system.