UPDATE BELOW
I run Kubuntu 14.04 on an Asus Prime notebook UX32A which has an 24GB SSD drive in addition to the HDD on which the OS is installed.
Since switching to Ubuntu I was never able to use suspend, the session would resume immediately after having closed user session.
After investigation is seems like it's the SSD drive that cannot be suspended.
Below is an extract from Dmesg :
[ 163.713133] PM: Syncing filesystems ... done.
[ 163.886898] PM: Preparing system for mem sleep
[ 163.887309] Freezing user space processes ... (elapsed 0.001 seconds) done.
[ 163.889158] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[ 163.890324] PM: Entering mem sleep
[ 163.891015] Suspending console(s) (use no_console_suspend to debug)
[ 163.891187] wlan0: deauthenticating from c4:3d:xx:xx:xx:39 by local choice (reason=3)
[ 163.933244] cfg80211: Calling CRDA to update world regulatory domain
[ 163.933412] sd 1:0:0:0: [sdb] Synchronizing SCSI cache
[ 163.933425] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 163.933497] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
[ 163.933499] ata2.00: irq_stat 0x40000001
[ 163.933502] ata2.00: failed command: FLUSH CACHE
[ 163.933510] ata2.00: cmd e7/00:00:00:00:00/00:00:00:00:00/a0 tag 8
[ 163.933510] res 51/04:00:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error)
[ 163.933513] ata2.00: status: { DRDY ERR }
[ 163.933515] ata2.00: error: { ABRT }
[ 163.933543] sd 0:0:0:0: [sda] Stopping disk
[ 163.934043] ata2.00: configured for UDMA/133
[ 163.934047] ata2.00: device reported invalid CHS sector 0
[ 163.934055] ata2: EH complete
[ 163.934124] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
[ 163.934126] ata2.00: irq_stat 0x40000001
[ 163.934128] ata2.00: failed command: FLUSH CACHE
[ 163.934141] ata2.00: cmd e7/00:00:00:00:00/00:00:00:00:00/a0 tag 9
[ 163.934141] res 51/04:00:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error)
[ 163.934142] ata2.00: status: { DRDY ERR }
[ 163.934144] ata2.00: error: { ABRT }
[ 163.934509] ata2.00: configured for UDMA/133
[ 163.934512] ata2.00: device reported invalid CHS sector 0
[ 163.934519] ata2: EH complete
[ 163.934581] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
[ 163.934582] ata2.00: irq_stat 0x40000001
[ 163.934584] ata2.00: failed command: FLUSH CACHE
[ 163.934589] ata2.00: cmd e7/00:00:00:00:00/00:00:00:00:00/a0 tag 10
[ 163.934589] res 51/04:00:00:00:00/00:00:00:00:00/a0 Emask 0x1 (device error)
[ 163.934590] ata2.00: status: { DRDY ERR }
[ 163.934592] ata2.00: error: { ABRT }
[ 163.934947] ata2.00: configured for UDMA/133
[ 163.934949] ata2.00: device reported invalid CHS sector 0
[ 163.934954] ata2: EH complete
[ 163.934958] sd 1:0:0:0: [sdb]
[ 163.934959] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[ 163.934961] sd 1:0:0:0: [sdb]
[ 163.934964] Sense Key : Aborted Command [current] [descriptor]
[ 163.934965] sd 1:0:0:0: [sdb]
[ 163.934967] Add. Sense: No additional sense information
[ 163.934977] dpm_run_callback(): scsi_bus_suspend+0x0/0x40 returns -5
[ 163.934982] PM: Device 1:0:0:0 failed to suspend async: error -5
[ 164.506235] PM: Some devices failed to suspend, or early wake event detected
[ 164.506441] sd 0:0:0:0: [sda] Starting disk
[ 165.171009] iwlwifi 0000:02:00.0: L1 Disabled; Enabling L0S
[ 165.177816] iwlwifi 0000:02:00.0: Radio type=0x2-0x1-0x0
[ 165.270265] PM: resume of devices complete after 763.734 msecs
[ 165.270597] PM: Finishing wakeup.
[ 165.270599] Restarting tasks ... done.
Anyone has an idea how to trouble shoot the issue and solve it?
If it is the SSD that prevents suspend, I would be fine with completely disabling it.
Thanks in advance
UPDATE:
Found a workaround in this post
I applied the workaround detailed in the validated answer and it seems to work fine.
