Description of problem:
Happened spontaneously while machine was idle.

Additional info:
reporter:       libreport-2.5.1
WARNING: CPU: 0 PID: 75 at drivers/gpu/drm/i915/intel_uncore.c:69 assert_device_not_suspended.isra.10+0x4c/0x60 [i915]()
Device suspended
Modules linked in: rfcomm nf_conntrack_netbios_ns nf_conntrack_broadcast fuse ccm ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw bnep arc4 ath9k ath9k_common ath9k_hw ath mac80211 intel_rapl iosf_mbi x86_pkg_temp_thermal coretemp kvm_intel kvm snd_hda_codec_hdmi snd_hda_codec_realtek iTCO_wdt ath3k iTCO_vendor_support asus_nb_wmi snd_hda_codec_generic asus_wmi sparse_keymap uvcvideo crct10dif_pclmul snd_hda_intel crc32_pclmul crc32c_intel btusb snd_hda_controller videobuf2_vmalloc
 snd_hda_codec videobuf2_core bluetooth videobuf2_memops cfg80211 ghash_clmulni_intel v4l2_common videodev snd_hwdep snd_seq snd_seq_device snd_pcm media joydev serio_raw snd_timer mei_me rfkill lpc_ich i2c_i801 snd mfd_core mei shpchp soundcore wmi i915 i2c_algo_bit drm_kms_helper drm video
CPU: 0 PID: 75 Comm: kswapd0 Not tainted 4.0.4-301.fc22.x86_64 #1
Hardware name: ASUSTeK Computer Inc. UX21E/UX21E, BIOS UX21E.214 11/22/2012
 0000000000000000 0000000069fe57ef ffff8800b4197968 ffffffff81782644
 0000000000000000 ffff8800b41979c0 ffff8800b41979a8 ffffffff8109c66a
 0000000000000008 ffff880036520068 0000000000100028 ffff880036520000
Call Trace:
 [<ffffffff81782644>] dump_stack+0x45/0x57
 [<ffffffff8109c66a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8109c6f5>] warn_slowpath_fmt+0x55/0x70
 [<ffffffffa00ecadc>] assert_device_not_suspended.isra.10+0x4c/0x60 [i915]
 [<ffffffffa00edba8>] gen6_write32+0x38/0xf0 [i915]
 [<ffffffffa00cb438>] i915_gem_write_fence+0x268/0x5c0 [i915]
 [<ffffffffa00cb82a>] i915_gem_object_update_fence+0x9a/0xd0 [i915]
 [<ffffffffa00cb8e6>] i915_gem_object_put_fence+0x86/0xe0 [i915]
 [<ffffffffa00cbacb>] i915_vma_unbind+0x18b/0x250 [i915]
 [<ffffffffa00cbe62>] i915_gem_shrink+0x162/0x270 [i915]
 [<ffffffffa00cc858>] i915_gem_shrinker_scan+0xb8/0xd0 [i915]
 [<ffffffff811b20f9>] shrink_slab+0x219/0x3d0
 [<ffffffff811b6c7c>] shrink_zone+0x2dc/0x2f0
 [<ffffffff811b7d00>] kswapd+0x540/0x9d0
 [<ffffffff811b77c0>] ? mem_cgroup_shrink_node_zone+0x180/0x180
 [<ffffffff810bb678>] kthread+0xd8/0xf0
 [<ffffffff810bb5a0>] ? kthread_worker_fn+0x180/0x180
 [<ffffffff81788bd8>] ret_from_fork+0x58/0x90
 [<ffffffff810bb5a0>] ? kthread_worker_fn+0x180/0x180