Description of problem:
Not sure.

Additional info:
reporter:       libreport-2.3.0
WARNING: CPU: 0 PID: 737 at drivers/gpu/drm/i915/intel_display.c:1278 assert_plane.constprop.78+0x6b/0x70 [i915]()
plane A assertion failure (expected on, current off)
Modules linked in: xt_CHECKSUM ipt_MASQUERADE tun ip6t_rpfilter ip6t_REJECT 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 x86_pkg_temp_thermal coretemp kvm_intel cdc_mbim kvm cdc_ncm snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core v4l2_common snd_hda_intel videodev snd_hda_controller usbnet snd_hda_codec media arc4 uas usb_storage snd_hwdep iwlmvm mii mac80211 iTCO_wdt crct10dif_pclmul iTCO_vendor_support crc32_pclmul cdc_acm
 cdc_wdm crc32c_intel i915 ghash_clmulni_intel btusb e1000e snd_seq snd_seq_device snd_pcm bluetooth ptp i2c_algo_bit drm_kms_helper thinkpad_acpi iwlwifi pps_core drm snd_timer lpc_ich mfd_core snd tpm_tis cfg80211 soundcore shpchp mei_me mei i2c_i801 joydev rfkill serio_raw wmi tpm video
CPU: 0 PID: 737 Comm: Xorg.bin Not tainted 3.17.4-300.fc21.x86_64 #1
Hardware name: LENOVO 20AQCTO1WW/20AQCTO1WW, BIOS GJET78WW (2.28 ) 07/29/2014
 0000000000000000 00000000b0ca10d7 ffff8802fbd4f8a8 ffffffff8173f929
 ffff8802fbd4f8f0 ffff8802fbd4f8e0 ffffffff810970ad 0000000000000000
 ffff880306893000 ffff8800c926f000 ffff8803058f0000 0000000000000000
Call Trace:
 [<ffffffff8173f929>] dump_stack+0x45/0x56
 [<ffffffff810970ad>] warn_slowpath_common+0x7d/0xa0
 [<ffffffff8109712c>] warn_slowpath_fmt+0x5c/0x80
 [<ffffffffa0354ffb>] assert_plane.constprop.78+0x6b/0x70 [i915]
 [<ffffffffa035a361>] hsw_disable_ips+0x41/0x190 [i915]
 [<ffffffffa0360c59>] intel_crtc_disable_planes+0x49/0x160 [i915]
 [<ffffffffa0361b77>] haswell_crtc_disable+0x57/0x340 [i915]
 [<ffffffffa035b801>] __intel_set_mode+0x7e1/0x16f0 [i915]
 [<ffffffff8101f3a7>] ? __switch_to_xtra+0x167/0x1a0
 [<ffffffffa0364126>] intel_set_mode+0x16/0x30 [i915]
 [<ffffffffa036527a>] intel_crtc_set_config+0xa9a/0xeb0 [i915]
 [<ffffffffa0139a34>] drm_mode_set_config_internal+0x64/0xe0 [drm]
 [<ffffffffa01c0df5>] drm_fb_helper_pan_display+0x95/0xf0 [drm_kms_helper]
 [<ffffffff813f3cfa>] fb_pan_display+0x9a/0x160
 [<ffffffff813edda0>] bit_update_start+0x20/0x50
 [<ffffffff813ec29e>] fbcon_switch+0x3ae/0x5e0
 [<ffffffff8146b699>] redraw_screen+0x1a9/0x250
 [<ffffffff81461ddf>] complete_change_console+0x3f/0xe0
 [<ffffffff8146301d>] vt_ioctl+0x119d/0x1430
 [<ffffffff8145695d>] tty_ioctl+0x2ad/0xbf0
 [<ffffffff810cda0b>] ? put_prev_entity+0x5b/0x400
 [<ffffffff8101f3a7>] ? __switch_to_xtra+0x167/0x1a0
 [<ffffffff81220910>] do_vfs_ioctl+0x2d0/0x4b0
 [<ffffffff81220b71>] SyS_ioctl+0x81/0xa0
 [<ffffffff81746ae9>] system_call_fastpath+0x16/0x1b