[   44.720091] ------------[ cut here ]------------
[   44.720113] WARNING: CPU: 1 PID: 1189 at drivers/gpu/drm/drm_irq.c:770 send_vblank_event+0xe1/0xf0 [drm]()
[   44.720115] Modules linked in: vhost_net vhost macvtap macvlan ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack xt_CHECKSUM iptable_mangle tun bridge stp llc ip6table_filter ip6_tables ebtable_nat ebtables arc4 md4 nls_utf8 cifs dns_resolver fscache bnep bluetooth cfg80211 rfkill x86_pkg_temp_thermal coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ppdev dcdbas iTCO_wdt iTCO_vendor_support snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_seq snd_seq_device joydev snd_pcm microcode serio_raw snd_timer snd soundcore lpc_ich mei_me i2c_i801 shpchp mfd_core mei tpm_tis tpm parport_pc parport nfsd auth_rpcgss nfs_acl lockd sunrpc i915 e1000e
[   44.720139]  ptp pps_core i2c_algo_bit drm_kms_helper drm i2c_core video
[   44.720143] CPU: 1 PID: 1189 Comm: Xorg Not tainted 3.15.4-200.fc20.x86_64 #1
[   44.720145] Hardware name: Dell Inc. Precision T1600/06NWYK, BIOS A02 04/11/2011
[   44.720146]  0000000000000000 0000000091781590 ffff880036877c40 ffffffff816ef2b1
[   44.720148]  0000000000000000 ffff880036877c78 ffffffff8108934d ffff8804017d2d80
[   44.720150]  ffff8800c5a12800 ffff8800c5a12a00 ffff8804171f5000 ffff8804017d2540
[   44.720151] Call Trace:
[   44.720157]  [<ffffffff816ef2b1>] dump_stack+0x45/0x56
[   44.720159]  [<ffffffff8108934d>] warn_slowpath_common+0x7d/0xa0
[   44.720161]  [<ffffffff8108947a>] warn_slowpath_null+0x1a/0x20
[   44.720167]  [<ffffffffa002a561>] send_vblank_event+0xe1/0xf0 [drm]
[   44.720173]  [<ffffffffa002a5fb>] drm_send_vblank_event+0x8b/0xe0 [drm]
[   44.720188]  [<ffffffffa0131fc3>] intel_crtc_page_flip+0x1b3/0x430 [i915]
[   44.720197]  [<ffffffffa0037a7f>] drm_mode_page_flip_ioctl+0x15f/0x310 [drm]
[   44.720203]  [<ffffffffa0026a79>] drm_ioctl+0x229/0x600 [drm]
[   44.720211]  [<ffffffffa0037920>] ? drm_mode_gamma_get_ioctl+0xf0/0xf0 [drm]
[   44.720213]  [<ffffffff811f94a0>] do_vfs_ioctl+0x2e0/0x4a0
[   44.720215]  [<ffffffff811f96e1>] SyS_ioctl+0x81/0xa0
[   44.720218]  [<ffffffff8111fac6>] ? __audit_syscall_exit+0x1f6/0x2a0
[   44.720220]  [<ffffffff816ff2e9>] system_call_fastpath+0x16/0x1b
[   44.720221] ---[ end trace 433afeb3d1da38f4 ]---