Additional info:
reporter:       libreport-2.2.3
WARNING: CPU: 1 PID: 64 at drivers/gpu/drm/drm_irq.c:1121 drm_wait_one_vblank+0x183/0x1b0 [drm]()
vblank not available on crtc 0, ret=-22
Modules linked in: i915 i2c_algo_bit ata_generic drm_kms_helper pata_acpi sky2 drm video
CPU: 1 PID: 64 Comm: kworker/u4:5 Not tainted 3.19.3-100.fc20.x86_64 #1
Hardware name: Hewlett-Packard         /308A, BIOS 68PVU Ver. F.0B 11/20/2009
Workqueue: events_unbound async_run_entry_fn
 0000000000000000 00000000e604adbf ffff880036c03778 ffffffff8175affa
 0000000000000000 ffff880036c037d0 ffff880036c037b8 ffffffff8109ad5a
 ffff880036c037c8 ffff8800371f0000 ffff8800371cb000 0000000000000000
Call Trace:
 [<ffffffff8175affa>] dump_stack+0x45/0x57
 [<ffffffff8109ad5a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8109ade5>] warn_slowpath_fmt+0x55/0x70
 [<ffffffffa0014873>] drm_wait_one_vblank+0x183/0x1b0 [drm]
 [<ffffffffa00f0bef>] ? gen4_read32+0x4f/0xc0 [i915]
 [<ffffffffa0144375>] intel_enable_tv+0x25/0x60 [i915]
 [<ffffffffa010dddb>] i9xx_crtc_enable+0x3fb/0x4a0 [i915]
 [<ffffffffa010c3d2>] __intel_set_mode+0x892/0xc80 [i915]
 [<ffffffffa011234b>] intel_set_mode+0x7b/0xb0 [i915]
 [<ffffffffa011260c>] intel_get_load_detect_pipe+0x28c/0x610 [i915]
 [<ffffffffa0144f64>] intel_tv_detect+0x134/0x5b0 [i915]
 [<ffffffff810feb40>] ? internal_add_timer+0xb0/0xb0
 [<ffffffffa008ac13>] drm_helper_probe_single_connector_modes_merge_bits+0x323/0x420 [drm_kms_helper]
 [<ffffffffa008ad23>] drm_helper_probe_single_connector_modes+0x13/0x20 [drm_kms_helper]
 [<ffffffffa0094580>] drm_fb_helper_probe_connector_modes.isra.3+0x50/0x70 [drm_kms_helper]
 [<ffffffffa00958ac>] drm_fb_helper_initial_config+0x5c/0x3d0 [drm_kms_helper]
 [<ffffffff8101357c>] ? __switch_to+0xdc/0x570
 [<ffffffffa0121fdb>] intel_fbdev_initial_config+0x1b/0x20 [i915]
 [<ffffffff810bbcda>] async_run_entry_fn+0x4a/0x140
 [<ffffffff810b3878>] process_one_work+0x148/0x3d0
 [<ffffffff810b3f3b>] worker_thread+0x11b/0x460
 [<ffffffff810b3e20>] ? rescuer_thread+0x320/0x320
 [<ffffffff810b9128>] kthread+0xd8/0xf0
 [<ffffffff810b9050>] ? kthread_create_on_node+0x1b0/0x1b0
 [<ffffffff817622d8>] ret_from_fork+0x58/0x90
 [<ffffffff810b9050>] ? kthread_create_on_node+0x1b0/0x1b0

Potential duplicate: bug 1209024