Description of problem:
Logged out of GNOME and instead of gdm/login screen, screen went black, and I couldn't switch to any tty. Definitely a regression, but not sure how reproducible this is yet, it doesn't always happen.

Additional info:
reporter:       libreport-2.4.0
WARNING: CPU: 0 PID: 699 at drivers/gpu/drm/i915/i915_gem.c:4285 i915_gem_object_unpin_fence+0x75/0xa0 [i915]()
WARN_ON(dev_priv->fence_regs[obj->fence_reg].pin_count <= 0)
Modules linked in: dm_crypt loop mmc_block rfcomm fuse xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun ccm nf_conntrack_netbios_ns nf_conntrack_broadcast ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack bnep ebtable_nat ebtable_broute bridge 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 arc4 b43 mac80211 nls_utf8 hfsplus cfg80211 snd_hda_codec_cirrus snd_hda_codec_generic intel_rapl iosf_mbi x86_pkg_temp_thermal coretemp kvm_intel snd_hda_intel snd_hda_controller kvm ssb iTCO_wdt snd_hda_codec iTCO_vendor_support uvcvideo crct10dif_pclmul applesmc
 crc32_pclmul btusb videobuf2_vmalloc input_polldev snd_hwdep bluetooth ghash_clmulni_intel videobuf2_core snd_seq videobuf2_memops v4l2_common videodev i2c_i801 snd_seq_device lpc_ich media hid_appleir rfkill bcm5974 snd_pcm bcma mfd_core snd_timer mei_me sbs snd mei sbshc apple_gmux apple_bl shpchp soundcore nfsd auth_rpcgss nfs_acl lockd grace sunrpc btrfs xor raid6_pq i915 8021q garp stp llc mrp i2c_algo_bit firewire_ohci drm_kms_helper firewire_core tg3 drm crc_itu_t sdhci_pci sdhci crc32c_intel mmc_core ptp pps_core video
CPU: 0 PID: 699 Comm: systemd-logind Not tainted 4.0.0-0.rc1.git0.1.fc22.x86_64 #1
Hardware name: Apple Inc. MacBookPro8,2/Mac-94245A3940C91C80, BIOS    MBP81.88Z.0047.B27.1201241646 01/24/12
 0000000000000000 0000000078694679 ffff88035fc1f6c8 ffffffff8177fc48
 0000000000000000 ffff88035fc1f720 ffff88035fc1f708 ffffffff8109c7ba
 ffff88035fc1f768 ffff88035c200000 ffff88034d422f40 ffffffffa021af60
Call Trace:
 [<ffffffff8177fc48>] dump_stack+0x45/0x57
 [<ffffffff8109c7ba>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8109c845>] warn_slowpath_fmt+0x55/0x70
 [<ffffffffa018b8f5>] i915_gem_object_unpin_fence+0x75/0xa0 [i915]
 [<ffffffffa01c74c5>] intel_unpin_fb_obj+0x25/0x60 [i915]
 [<ffffffffa01d388d>] intel_cleanup_plane_fb+0x3d/0x80 [i915]
 [<ffffffffa01308be>] drm_plane_helper_commit+0x1fe/0x300 [drm_kms_helper]
 [<ffffffffa0130a5a>] drm_plane_helper_update+0x9a/0xf0 [drm_kms_helper]
 [<ffffffffa01d3396>] intel_crtc_set_config+0xdb6/0x1010 [i915]
 [<ffffffffa0098056>] drm_mode_set_config_internal+0x66/0x100 [drm]
 [<ffffffffa0139738>] restore_fbdev_mode+0xc8/0xf0 [drm_kms_helper]
 [<ffffffffa013b789>] drm_fb_helper_restore_fbdev_mode_unlocked+0x29/0x80 [drm_kms_helper]
 [<ffffffffa013b802>] drm_fb_helper_set_par+0x22/0x50 [drm_kms_helper]
 [<ffffffffa01e2a8a>] intel_fbdev_set_par+0x1a/0x60 [i915]
 [<ffffffff81417bc6>] ? fb_set_var+0x2f6/0x480
 [<ffffffff81417b06>] fb_set_var+0x236/0x480
 [<ffffffff810d4e6e>] ? check_preempt_wakeup+0xfe/0x230
 [<ffffffff810d3cbc>] ? update_curr+0x5c/0x160
 [<ffffffff8140d60c>] fbcon_blank+0x34c/0x390
 [<ffffffff814944da>] do_unblank_screen+0xda/0x1d0
 [<ffffffff81488b2d>] complete_change_console+0x5d/0xf0
 [<ffffffff81489fcb>] vt_ioctl+0x140b/0x1430
 [<ffffffff8147be01>] tty_ioctl+0x3f1/0xc30
 [<ffffffff8147cc70>] ? tty_release+0x320/0x5a0
 [<ffffffff810fbf47>] ? __call_rcu_nocb_enqueue+0xd7/0xe0
 [<ffffffff81235056>] do_vfs_ioctl+0x2c6/0x4d0
 [<ffffffff812352e1>] SyS_ioctl+0x81/0xa0
 [<ffffffff81786029>] system_call_fastpath+0x12/0x17