Ubuntu – Dell XPS 15 (9550) rebooting after suspend

I have a dell XPS (9550 revision – this is essentially the same hardware as the Precision 5510 which is available with Ubuntu out-of-the-box) and amazingly it pretty much always worked properly out of the box with 16.04. In the last few days though, suspend has stopped working, when on battery power¹.

Basically the laptop appears to suspend, but when I wake it up, it goes through the normal boot process.

Here are the last few lines from /var/log/syslog from the suspend logging:

Jan 14 13:06:10 xps15-laptop whoopsie[827]: [13:06:10] offline
Jan 14 13:06:11 xps15-laptop kernel: [   15.829125] IPv6: ADDRCONF(NETDEV_UP): wlp2s0: link is not ready
Jan 14 13:06:11 xps15-laptop wpa_supplicant[1300]: nl80211: deinit ifname=p2p-dev-wlp2s0 disabled_11b_rates=0
Jan 14 13:06:11 xps15-laptop nm-dispatcher: req:3 'down' [wlp2s0]: new request (1 scripts)
Jan 14 13:06:11 xps15-laptop nm-dispatcher: req:3 'down' [wlp2s0]: start running ordered scripts...
Jan 14 13:06:11 xps15-laptop wpa_supplicant[1300]: nl80211: deinit ifname=wlp2s0 disabled_11b_rates=0
Jan 14 13:06:12 xps15-laptop systemd[1]: Reached target Sleep.
Jan 14 13:06:12 xps15-laptop systemd[1]: Starting Suspend...
Jan 14 13:06:12 xps15-laptop systemd-sleep[2271]: Failed to connect to non-global ctrl_ifname: (nil)  error: No such file or directory
Jan 14 13:06:12 xps15-laptop systemd-sleep[2273]: /lib/systemd/system-sleep/wpasupplicant failed with error code 255.
Jan 14 13:06:12 xps15-laptop systemd-sleep[2271]: Suspending system...

Does anything jump out there? The lines following that seem to just be what'd you'd expect from a cold boot:

Jan 14 13:06:54 xps15-laptop rsyslogd: [origin software="rsyslogd" swVersion="8.16.0" x-pid="923" x-info="http://www.rsyslog.com"] start
Jan 14 13:06:54 xps15-laptop rsyslogd-2222: command 'KLogPermitNonKernelFacility' is currently not permitted - did you already set it via a RainerScript command (v6+ config)? [v8.16.0 try http
://www.rsyslog.com/e/2222 ]
Jan 14 13:06:54 xps15-laptop rsyslogd: rsyslogd's groupid changed to 109
Jan 14 13:06:54 xps15-laptop rsyslogd: rsyslogd's userid changed to 105
Jan 14 13:06:54 xps15-laptop systemd-modules-load[228]: Inserted module 'lp'
Jan 14 13:06:54 xps15-laptop systemd-modules-load[228]: Inserted module 'ppdev'
Jan 14 13:06:54 xps15-laptop systemd-modules-load[228]: Inserted module 'parport_pc'
Jan 14 13:06:54 xps15-laptop systemd[1]: Started Apply Kernel Variables.
Jan 14 13:06:54 xps15-laptop loadkeys[220]: Loading /etc/console-setup/cached.kmap.gz
Jan 14 13:06:54 xps15-laptop systemd[1]: Started Set console keymap.
Jan 14 13:06:54 xps15-laptop systemd[1]: Started Create Static Device Nodes in /dev.
Jan 14 13:06:54 xps15-laptop systemd[1]: Starting udev Kernel Device Manager...
Jan 14 13:06:54 xps15-laptop systemd[1]: Started udev Kernel Device Manager.
Jan 14 13:06:54 xps15-laptop systemd[1]: Starting Remount Root and Kernel File Systems...
Jan 14 13:06:54 xps15-laptop systemd[1]: Started Remount Root and Kernel File Systems.
Jan 14 13:06:54 xps15-laptop systemd[1]: Reached target Local File Systems (Pre).

Not too much has changed lately except that the kernel hit version 4.4.0-59 (previously was 4.4.0-57), and I tweaked a BIOS option to disable my embedded sound device (since restored with no change).

Finally, here's what a successful suspend/wakeup looks like (when on battery power):

Jan 14 13:15:49 xps15-laptop kernel: [  540.190809] IPv6: ADDRCONF(NETDEV_UP): wlp2s0: link is not ready
Jan 14 13:15:49 xps15-laptop wpa_supplicant[1298]: nl80211: deinit ifname=p2p-dev-wlp2s0 disabled_11b_rates=0
Jan 14 13:15:49 xps15-laptop dbus[803]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
Jan 14 13:15:49 xps15-laptop systemd[1]: Reached target Sleep.
Jan 14 13:15:49 xps15-laptop systemd[1]: Starting Suspend...
Jan 14 13:15:49 xps15-laptop systemd[1]: Starting Network Manager Script Dispatcher Service...
Jan 14 13:15:49 xps15-laptop dbus[803]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Jan 14 13:15:49 xps15-laptop systemd[1]: Started Network Manager Script Dispatcher Service.
Jan 14 13:15:49 xps15-laptop nm-dispatcher: req:1 'down' [wlp2s0]: new request (1 scripts)
Jan 14 13:15:49 xps15-laptop nm-dispatcher: req:1 'down' [wlp2s0]: start running ordered scripts...
Jan 14 13:15:49 xps15-laptop wpa_supplicant[1298]: nl80211: deinit ifname=wlp2s0 disabled_11b_rates=0
Jan 14 13:15:54 xps15-laptop whoopsie[931]: [13:15:54] Cannot reach: https://daisy.ubuntu.com
Jan 14 13:15:54 xps15-laptop whoopsie[931]: [13:15:54] offline
Jan 14 13:15:54 xps15-laptop whoopsie[931]: [13:15:54] Cannot reach: https://daisy.ubuntu.com
Jan 14 13:15:59 xps15-laptop systemd-sleep[2690]: Selected interface 'wlp2s0'
Jan 14 13:15:59 xps15-laptop systemd-sleep[2690]: 'SUSPEND' command timed out.
Jan 14 13:15:59 xps15-laptop systemd-sleep[2696]: /lib/systemd/system-sleep/wpasupplicant failed with error code 254.
Jan 14 13:15:59 xps15-laptop systemd-sleep[2690]: Suspending system...
Jan 14 13:16:52 xps15-laptop kernel: [  550.254337] PM: Syncing filesystems ... done.
Jan 14 13:16:52 xps15-laptop kernel: [  550.268354] PM: Preparing system for sleep (mem)
Jan 14 13:16:52 xps15-laptop kernel: [  550.268979] Freezing user space processes ... (elapsed 0.002 seconds) done.
Jan 14 13:16:52 xps15-laptop kernel: [  550.271751] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
Jan 14 13:16:52 xps15-laptop kernel: [  550.273159] PM: Suspending system (mem)
Jan 14 13:16:52 xps15-laptop kernel: [  550.273197] Suspending console(s) (use no_console_suspend to debug)
Jan 14 13:16:52 xps15-laptop kernel: [  550.486068] brcmf_fil_cmd_data: bus is down. we have nothing to do.
Jan 14 13:16:52 xps15-laptop kernel: [  550.613975] nouveau 0000:01:00.0: DRM: resuming kernel object tree...
Jan 14 13:16:52 xps15-laptop kernel: [  550.717482] nouveau 0000:01:00.0: priv: HUB0: 10ecc0 ffffffff (1d40822c)
Jan 14 13:16:52 xps15-laptop kernel: [  550.764382] nouveau 0000:01:00.0: DRM: resuming client object trees...
Jan 14 13:16:52 xps15-laptop kernel: [  550.764397] nouveau 0000:01:00.0: DRM: evicting buffers...
Jan 14 13:16:52 xps15-laptop kernel: [  550.764398] nouveau 0000:01:00.0: DRM: waiting for kernel channels to go idle...
Jan 14 13:16:52 xps15-laptop kernel: [  550.764412] nouveau 0000:01:00.0: DRM: suspending client object trees...
Jan 14 13:16:52 xps15-laptop kernel: [  550.765770] nouveau 0000:01:00.0: DRM: suspending kernel object tree...
Jan 14 13:16:52 xps15-laptop kernel: [  551.638247] PM: suspend of devices complete after 1155.310 msecs
Jan 14 13:16:52 xps15-laptop kernel: [  551.654829] PM: late suspend of devices complete after 16.561 msecs
Jan 14 13:16:52 xps15-laptop kernel: [  551.656867] xhci_hcd 0000:00:14.0: System wakeup enabled by ACPI
Jan 14 13:16:52 xps15-laptop kernel: [  551.671878] PM: noirq suspend of devices complete after 17.027 msecs
Jan 14 13:16:52 xps15-laptop kernel: [  551.672619] ACPI: Preparing to enter system sleep state S3
Jan 14 13:16:52 xps15-laptop kernel: [  551.695080] ACPI : EC: EC stopped
Jan 14 13:16:52 xps15-laptop kernel: [  551.695082] PM: Saving platform NVS memory

Note that some of the messages "after" the wakeup (starting at 13:16:52) seem to actually be related to actions leading up to the suspend. I guess the logging facility shuts down at some point during the suspend so that messages after that point show up only after wakeup (so I don't get to see these in the failed case).

¹ In particular, suspend works fine if the laptop is on AC power during the entire suspect process – at the point of suspension, at the point of wake and all the time in between. Simply unplugging the AC adapter, even for a second, while the host is sleeping will cause the failure described above.