Additional info:
reporter:       libreport-2.3.0
WARNING: CPU: 0 PID: 2859 at drivers/gpu/drm/i915/intel_display.c:9713 intel_check_page_flip+0xdb/0xf0 [i915]()
Kicking stuck page flip: queued at 28520, now 28525
Modules linked in: mceusb rc_core rfcomm fuse xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun 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 vfat fat uvcvideo arc4 btusb rtl8723be videobuf2_vmalloc videobuf2_core btcoexist videobuf2_memops bluetooth v4l2_common rtl8723_common videodev media rtl_pci rtlwifi intel_rapl mac80211 snd_hda_codec_hdmi snd_hda_codec_via snd_hda_codec_generic snd_hda_intel snd_hda_controller coretemp kvm_intel kvm snd_intel_sst_acpi
 crct10dif_pclmul snd_intel_sst_core snd_soc_rt5640 crc32_pclmul snd_hda_codec crc32c_intel snd_soc_sst_mfld_platform snd_soc_rl6231 snd_soc_core ghash_clmulni_intel snd_compress snd_hwdep cfg80211 snd_seq iTCO_wdt iTCO_vendor_support rtsx_pci_ms memstick snd_seq_device mei_txe snd_pcm joydev dw_dmac serio_raw mei snd_timer wmi dw_dmac_core regmap_i2c snd shpchp lpc_ich rfkill_gpio i2c_hid soundcore i2c_i801 i2c_designware_platform iosf_mbi rfkill snd_soc_sst_acpi i2c_designware_core nfsd auth_rpcgss nfs_acl lockd grace sunrpc binfmt_misc i915 i2c_algo_bit drm_kms_helper drm rtsx_pci_sdmmc uas r8169 usb_storage rtsx_pci mfd_core mii sdhci_acpi video sdhci mmc_core
CPU: 0 PID: 2859 Comm: firefox Not tainted 3.19.2-201.fc21.x86_64 #1
Hardware name: GIGABYTE Q21/Q21, BIOS 1.03.09RGI4 09/01/2014
 0000000000000000 00000000ce7e2237 ffff88023fc03ce8 ffffffff8176e025
 0000000000000000 ffff88023fc03d40 ffff88023fc03d28 ffffffff8109bc0a
 ffff88023fc03d28 ffff880233ac8000 ffff880233fee000 0000000000000000
Call Trace:
 <IRQ>  [<ffffffff8176e025>] dump_stack+0x45/0x57
 [<ffffffff8109bc0a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8109bc95>] warn_slowpath_fmt+0x55/0x70
 [<ffffffffa019345b>] intel_check_page_flip+0xdb/0xf0 [i915]
 [<ffffffffa015c5f6>] valleyview_pipestat_irq_handler+0x206/0x210 [i915]
 [<ffffffffa0161e01>] valleyview_irq_handler+0xc1/0x170 [i915]
 [<ffffffff810f2957>] handle_irq_event_percpu+0x77/0x1a0
 [<ffffffff810f2abb>] handle_irq_event+0x3b/0x60
 [<ffffffff810f5c7e>] handle_edge_irq+0x6e/0x120
 [<ffffffff81017444>] handle_irq+0x74/0x140
 [<ffffffff8177757f>] do_IRQ+0x4f/0xf0
 [<ffffffff8177536d>] common_interrupt+0x6d/0x6d
 <EOI> 

Potential duplicate: bug 1207169