Bug 1222273

Can you get any backtraces for these crashes?  (drkonqi or abrt)?

It's very likely to be video driver related, but that's just speculation without backtrace details.

I believe this is a duplicate of bug 1221050.

How so?  the linked bug is about suspend/resume, not lock screen.

The underlying cause is the same, I believe. Note that OP is not referring to the lock screen here, but to the lock screen specifically after a few hours of idelenss. Try downgrading the kernel to 3.19 as mentioned in bug 1221050; it might prove to be a workaround for this issue as well.

I think the kactivitymanager crashes may have generated notifications after the reboot - is there someone I can look to see if the stack traces are still available?

ABRT didn't seem to trigger at all for any of them, but I'll look there as well.

As far as bug 1221050 goes, it's plausible they'll turn out to have a common driver related cause, but I wouldn't be prepared to call them duplicates yet. However, I'll check to see if I can reproduce bug 1221050 using suspend/resume explicitly (I tend not to rely on suspend/resume normally)

I can reproduce bug 1221050, and it looks like abrt already reported most of the various segfaults I saw in the logs (details below). Since I don't think there's anything particularly useful that can be investigated further here, and there are known issues with kernel compatibility on the Spectre 360's Broadwell chipset, I think duping this onto the pm-suspend/hibernate bug is a reasonable way to go.

$ abrt-cli ls
id a82b46675f72cb6e34dc994e7fe0b472096ea691
reason:         tracker-miner-apps killed by SIGSEGV
time:           Sat 16 May 2015 17:57:39 AEST
cmdline:        /usr/libexec/tracker-miner-apps
package:        tracker-1.4.0-1.fc22
uid:            1000 (ncoghlan)
count:          1
Directory:      /var/tmp/abrt/ccpp-2015-05-16-17:57:39-2358

id 5738ab6cb90c0f0d31844f903a1ca8d2a3477805
reason:         kded5 killed by SIGSEGV
time:           Sat 09 May 2015 14:31:44 AEST
cmdline:        /usr/bin/kded5
package:        kf5-kded-5.9.0-1.fc22
uid:            1000 (ncoghlan)
count:          2
Directory:      /var/tmp/abrt/ccpp-2015-05-09-14:31:44-2912
Reported:       https://retrace.fedoraproject.org/faf/reports/bthash/39b0ae52bde5567a43151468934723b5cc5b76c3

id 1d8e7ca89055a21b717b60a7242d87bc51e321ac
reason:         kscreenlocker_greet killed by SIGABRT
time:           Mon 04 May 2015 00:10:05 AEST
cmdline:        /usr/libexec/kscreenlocker_greet --graceTime 4744 --ksldfd 32
package:        plasma-workspace-5.3.0-1.fc22
uid:            1000 (ncoghlan)
count:          1
Directory:      /var/tmp/abrt/ccpp-2015-05-04-00:10:05-32765
Reported:       https://retrace.fedoraproject.org/faf/reports/bthash/515e4fdb79c4df8d8322c1906f08d1e4d8605b9c

id b88f287f9b84160a92f069195d5e41e2a292e60d
reason:         WARNING: CPU: 0 PID: 1748 at drivers/gpu/drm/i915/intel_display.c:1260 assert_plane.constprop.80+0x74/0xb0 [i915]() [i915]
time:           Thu 23 Apr 2015 20:43:05 AEST
cmdline:        BOOT_IMAGE=/vmlinuz-4.0.0-0.rc5.git4.1.fc22.x86_64 root=/dev/mapper/fedora_thechalk-root ro rd.luks.uuid=luks-827c1b02-e4e8-4246-b939-d392850c1762 rd.lvm.lv=fedora_thechalk/swap rd.lvm.lv=fedora_thechalk/root rhgb quiet LANG=en_AU.UTF-8
package:        kernel
count:          3
Directory:      /var/tmp/abrt/oops-2015-04-23-20:43:05-973-0
Reported:       https://retrace.fedoraproject.org/faf/reports/bthash/94fac73ca67d8508dbbde162d09911a06aa092dc
                https://retrace.fedoraproject.org/faf/reports/615489/
                https://bugzilla.redhat.com/show_bug.cgi?id=1207233

id c0993852ee6e320144f2484d4f447b928c1ad3b6
reason:         kactivitymanagerd killed by SIGSEGV
time:           Sun 26 Apr 2015 13:44:37 AEST
cmdline:        /usr/bin/kactivitymanagerd -session 10dcc9d1ce000142998930600000021390006_1430019839_4450
package:        kf5-kactivities-5.9.0-1.fc22
uid:            1000 (ncoghlan)
count:          1
Directory:      /var/tmp/abrt/ccpp-2015-04-26-13:44:37-8576
Reported:       https://retrace.fedoraproject.org/faf/reports/bthash/e36b61f1c7fafaa8e57a47ea08d5ae31f424c98e
                https://retrace.fedoraproject.org/faf/reports/458854/
                https://bugzilla.redhat.com/show_bug.cgi?id=1210559

*** This bug has been marked as a duplicate of bug 1221050 ***

The Intel i915 graphics driver issues described in bug 1188772 seem like a more plausible culprit here.

*** This bug has been marked as a duplicate of bug 1188772 ***