Description of problem:
Left an rsync(1M) running to backup partition and then left for a couple hours.
When I got back my rsync had completed successfully and then I noticed this error.
It has been happening for a couple of weeks now with various kernels.

Additional info:
reporter:       libreport-2.3.0
WARNING: CPU: 3 PID: 804 at drivers/gpu/drm/drm_irq.c:1121 drm_wait_one_vblank+0x190/0x1a0 [drm]()
vblank not available on crtc 1, ret=-22
Modules linked in: bnep bluetooth fuse snd_pcm_oss snd_mixer_oss nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack coretemp snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec kvm crct10dif_pclmul snd_hwdep iTCO_wdt snd_seq snd_seq_device iTCO_vendor_support crc32_pclmul snd_pcm arc4 rtl8192se rtl_pci uvcvideo rtlwifi crc32c_intel videobuf2_vmalloc ghash_clmulni_intel videobuf2_core videobuf2_memops v4l2_common videodev thinkpad_acpi media mac80211 ppdev snd_timer mxm_wmi snd cfg80211 sdhci_pci lpc_ich joydev sdhci mmc_core serio_raw parport_pc intel_ips soundcore rfkill mfd_core wmi tpm_tis tpm parport mei_me shpchp i2c_i801 mei acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd
 grace sunrpc binfmt_misc i915 i2c_algo_bit drm_kms_helper uas usb_storage firewire_ohci drm e1000e firewire_core crc_itu_t ptp pps_core video
CPU: 3 PID: 804 Comm: Xorg.bin Not tainted 3.19.3-200.fc21.x86_64 #1
Hardware name: LENOVO 2516DCU/2516DCU, BIOS 6IET75WW (1.35 ) 02/01/2011
 0000000000000000 000000002b721873 ffff8801b3327ac8 ffffffff8176e215
 0000000000000000 ffff8801b3327b20 ffff8801b3327b08 ffffffff8109bc1a
 ffff880036a616b0 ffff880036480000 ffff8800b57cf800 0000000000000001
Call Trace:
 [<ffffffff8176e215>] dump_stack+0x45/0x57
 [<ffffffff8109bc1a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8109bca5>] warn_slowpath_fmt+0x55/0x70
 [<ffffffffa0084910>] ? drm_wait_one_vblank+0x170/0x1a0 [drm]
 [<ffffffffa0084930>] drm_wait_one_vblank+0x190/0x1a0 [drm]
 [<ffffffffa0196e34>] ? ilk_audio_codec_disable+0x104/0x1b0 [i915]
 [<ffffffffa01d8e77>] intel_disable_hdmi+0x1c7/0x200 [i915]
 [<ffffffffa01aacfa>] ironlake_crtc_disable+0x15a/0x7f0 [i915]
 [<ffffffffa01ac619>] intel_crtc_control+0x59/0x120 [i915]
 [<ffffffffa01ac741>] intel_crtc_update_dpms+0x61/0x70 [i915]
 [<ffffffffa01b22e1>] intel_connector_dpms+0x61/0x70 [i915]
 [<ffffffffa0092c59>] drm_mode_obj_set_property_ioctl+0x369/0x370 [drm]
 [<ffffffffa0092c9f>] drm_mode_connector_property_set_ioctl+0x3f/0x60 [drm]
 [<ffffffffa0082a9f>] drm_ioctl+0x1df/0x680 [drm]
 [<ffffffff8122e298>] do_vfs_ioctl+0x2f8/0x500
 [<ffffffff810a8071>] ? __set_task_blocked+0x41/0xa0
 [<ffffffff8113dba4>] ? __audit_syscall_entry+0xb4/0x110
 [<ffffffff81022dfc>] ? do_audit_syscall_entry+0x6c/0x70
 [<ffffffff8122e521>] SyS_ioctl+0x81/0xa0
 [<ffffffff8113ddf6>] ? __audit_syscall_exit+0x1f6/0x2a0
 [<ffffffff81774a09>] system_call_fastpath+0x12/0x17