Passage à Jessie : l'ordinateur se met en veille de manière impromptue

Salut, depuis systemd un de mes ordinateurs se met en veille sans aucune raison et de manière aléatoire dans le temps (parfois l'ordinateur se met en veille 3 fois en 5 min, puis après plus rien pendant 30 min).
Journalctl ne m'en dit pas beaucoup plus:

sept. 27 14:38:42 netbook systemd-logind[454]: Suspending...
sept. 27 14:38:42 netbook systemd-sleep[1866]: Suspending system...
sept. 27 14:38:46 netbook kernel: PM: Syncing filesystems ... done.
sept. 27 14:38:46 netbook kernel: PM: Preparing system for mem sleep
sept. 27 14:38:46 netbook kernel: Freezing user space processes ... (elapsed 0.001 seconds) done.
sept. 27 14:38:46 netbook kernel: Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
sept. 27 14:38:46 netbook kernel: PM: Entering mem sleep
sept. 27 14:38:46 netbook kernel: Suspending console(s) (use no_console_suspend to debug)
sept. 27 14:38:46 netbook kernel: wlan0: deauthenticating from 30:7e:cb:9c:20:04 by local choice (Reason: 3=DEAUTH_LEAVING)
sept. 27 14:38:46 netbook kernel: queueing ieee80211 work while going to suspend
sept. 27 14:38:46 netbook kernel: cfg80211: Exceeded CRDA call max attempts. Not calling CRDA
sept. 27 14:38:46 netbook kernel: sd 0:0:0:0: [sda] Synchronizing SCSI cache
sept. 27 14:38:46 netbook kernel: sd 0:0:0:0: [sda] Stopping disk
sept. 27 14:38:46 netbook kernel: PM: suspend of devices complete after 870.526 msecs
sept. 27 14:38:46 netbook kernel: PM: late suspend of devices complete after 15.896 msecs
sept. 27 14:38:46 netbook kernel: r8169 0000:02:00.0: System wakeup enabled by ACPI
sept. 27 14:38:46 netbook kernel: PM: noirq suspend of devices complete after 16.102 msecs
sept. 27 14:38:46 netbook kernel: ACPI: Preparing to enter system sleep state S3
sept. 27 14:38:46 netbook kernel: ACPI : EC: EC stopped
sept. 27 14:38:46 netbook kernel: PM: Saving platform NVS memory
sept. 27 14:38:46 netbook kernel: Disabling non-boot CPUs ...
sept. 27 14:38:46 netbook kernel: smpboot: CPU 1 is now offline
sept. 27 14:38:46 netbook kernel: ACPI: Low-level resume complete
sept. 27 14:38:46 netbook kernel: ACPI : EC: EC started
sept. 27 14:38:46 netbook kernel: PM: Restoring platform NVS memory
sept. 27 14:38:46 netbook kernel: microcode: CPU0 microcode updated early to revision 0xa0b, date = 2010-09-28
sept. 27 14:38:46 netbook kernel: Enabling non-boot CPUs ...
sept. 27 14:38:46 netbook kernel: x86: Booting SMP configuration:
sept. 27 14:38:46 netbook kernel: smpboot: Booting Node 0 Processor 1 APIC 0x1
sept. 27 14:38:46 netbook kernel: microcode: CPU1 microcode updated early to revision 0xa0b, date = 2010-09-28
sept. 27 14:38:46 netbook kernel:  cache: parent cpu1 should not be sleeping
sept. 27 14:38:46 netbook kernel: Monitor-Mwait will be used to enter C-2 state
sept. 27 14:38:46 netbook kernel: CPU1 is up
sept. 27 14:38:46 netbook kernel: ACPI: Waking up from system sleep state S3
sept. 27 14:38:46 netbook kernel: PM: noirq resume of devices complete after 15.484 msecs
sept. 27 14:38:46 netbook kernel: PM: early resume of devices complete after 0.543 msecs
sept. 27 14:38:46 netbook kernel: usb usb2: root hub lost power or was reset
sept. 27 14:38:46 netbook kernel: usb usb4: root hub lost power or was reset
sept. 27 14:38:46 netbook kernel: usb usb5: root hub lost power or was reset
sept. 27 14:38:46 netbook kernel: r8169 0000:02:00.0: System wakeup disabled by ACPI
sept. 27 14:38:46 netbook kernel: usb usb3: root hub lost power or was reset
sept. 27 14:38:46 netbook kernel: sd 0:0:0:0: [sda] Starting disk
sept. 27 14:38:46 netbook kernel: usb usb7: root hub lost power or was reset
sept. 27 14:38:46 netbook kernel: usb usb6: root hub lost power or was reset
sept. 27 14:38:46 netbook kernel: r8169 0000:02:00.0 eth0: link down
sept. 27 14:38:46 netbook kernel: rtc_cmos 00:02: System wakeup disabled by ACPI
sept. 27 14:38:46 netbook kernel: ata2: SATA link down (SStatus 0 SControl 300)
sept. 27 14:38:46 netbook kernel: ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
sept. 27 14:38:46 netbook kernel: ata1.00: ACPI cmd c6/00:01:00:00:00:00 (SET MULTIPLE MODE) succeeded
sept. 27 14:38:46 netbook kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out
sept. 27 14:38:46 netbook kernel: ata1.00: ACPI cmd c6/00:01:00:00:00:00 (SET MULTIPLE MODE) succeeded
sept. 27 14:38:46 netbook kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:00 (SECURITY FREEZE LOCK) filtered out
sept. 27 14:38:46 netbook kernel: ata1.00: configured for UDMA/133
sept. 27 14:38:46 netbook kernel: ata5: SATA link down (SStatus 0 SControl 300)
sept. 27 14:38:46 netbook kernel: usb 6-1: reset full-speed USB device number 3 using uhci_hcd
sept. 27 14:38:46 netbook kernel: ata6: SATA link down (SStatus 0 SControl 300)
sept. 27 14:38:46 netbook kernel: usb 6-1: device firmware changed
sept. 27 14:38:46 netbook kernel: PM: resume of devices complete after 546.878 msecs
sept. 27 14:38:46 netbook kernel: PM: Finishing wakeup.
sept. 27 14:38:46 netbook kernel: Restarting tasks ...
 

Par où devrais-je regarder ?
Bon dimanche

Passage à Jessie : l'ordinateur se met en veille de manière impromptue