Additional info:
reporter:       libreport-2.2.2
WARNING: CPU: 0 PID: 210 at drivers/gpu/drm/i915/intel_panel.c:723 i965_enable_backlight+0x132/0x160 [i915]()
backlight already enabled
Modules linked in: btrfs xor usb_storage raid6_pq i915(+) atl1c i2c_algo_bit drm_kms_helper drm i2c_core video
CPU: 0 PID: 210 Comm: systemd-udevd Not tainted 3.14.4-200.fc20.x86_64 #1
Hardware name: ASUSTeK Computer Inc.         UL30A               /UL30A     , BIOS 212     12/28/2009
 0000000000000000 00000000618bf44f ffff88013841d260 ffffffff816ef1d2
 ffff88013841d2a8 ffff88013841d298 ffffffff8108a1bd ffff880036a4c000
 0000000000000000 ffff88003694e800 00000000e0000000 ffff880036904400
Call Trace:
 [<ffffffff816ef1d2>] dump_stack+0x45/0x56
 [<ffffffff8108a1bd>] warn_slowpath_common+0x7d/0xa0
 [<ffffffff8108a23c>] warn_slowpath_fmt+0x5c/0x80
 [<ffffffffa00f6b3c>] ? gen4_read32+0x3c/0xb0 [i915]
 [<ffffffffa00de4c2>] i965_enable_backlight+0x132/0x160 [i915]
 [<ffffffffa00df519>] intel_panel_enable_backlight+0xa9/0xe0 [i915]
 [<ffffffffa00f6cf0>] ? gen4_write8+0xa0/0xa0 [i915]
 [<ffffffffa00c92a8>] intel_enable_lvds+0x178/0x190 [i915]
 [<ffffffffa00f6cf0>] ? gen4_write8+0xa0/0xa0 [i915]
 [<ffffffffa00bda89>] i9xx_crtc_enable+0x2e9/0x410 [i915]
 [<ffffffffa00c03d7>] __intel_set_mode+0x767/0x1610 [i915]
 [<ffffffffa00c3726>] intel_set_mode+0x16/0x30 [i915]
 [<ffffffffa00c3feb>] intel_crtc_set_config+0x7bb/0x990 [i915]
 [<ffffffffa002da3d>] drm_mode_set_config_internal+0x5d/0xe0 [drm]
 [<ffffffffa007ef71>] drm_fb_helper_set_par+0x71/0xf0 [drm_kms_helper]
 [<ffffffff813bfef4>] fbcon_init+0x4f4/0x570
 [<ffffffff81435898>] visual_init+0xb8/0x120
 [<ffffffff81438283>] do_bind_con_driver+0x163/0x330
 [<ffffffff81438a34>] do_take_over_console+0x114/0x1c0
 [<ffffffff813bb733>] do_fbcon_takeover+0x63/0xd0
 [<ffffffff813c0a5d>] fbcon_event_notify+0x60d/0x720
 [<ffffffff816fa48c>] notifier_call_chain+0x4c/0x70
 [<ffffffff810b2c0d>] __blocking_notifier_call_chain+0x4d/0x70
 [<ffffffff810b2c46>] blocking_notifier_call_chain+0x16/0x20
 [<ffffffff813b21bb>] fb_notifier_call_chain+0x1b/0x20
 [<ffffffff813b4216>] register_framebuffer+0x1f6/0x340
 [<ffffffffa007ec4f>] drm_fb_helper_initial_config+0x33f/0x520 [drm_kms_helper]
 [<ffffffff811cc027>] ? __kmalloc+0x1f7/0x240
 [<ffffffffa007e0fe>] ? drm_fb_helper_init+0xfe/0x200 [drm_kms_helper]
 [<ffffffffa00f6d2f>] ? gen4_write32+0x3f/0xa0 [i915]
 [<ffffffffa00ff6f1>] intel_fbdev_initial_config+0x21/0x30 [i915]
 [<ffffffffa008c3e3>] i915_driver_load+0xe03/0xe30 [i915]
 [<ffffffffa0027ab5>] ? drm_get_minor+0x1a5/0x200 [drm]
 [<ffffffffa0027b8b>] drm_dev_register+0x7b/0x160 [drm]
 [<ffffffffa002a0c0>] drm_get_pci_dev+0xa0/0x220 [drm]
 [<ffffffffa00886fb>] i915_pci_probe+0x3b/0x60 [i915]
 [<ffffffff81394c25>] local_pci_probe+0x45/0xa0
 [<ffffffff81396019>] pci_device_probe+0xf9/0x150
 [<ffffffff81465045>] driver_probe_device+0x125/0x3a0
 [<ffffffff81465393>] __driver_attach+0x93/0xa0
 [<ffffffff81465300>] ? __device_attach+0x40/0x40
 [<ffffffff81462e73>] bus_for_each_dev+0x73/0xc0
 [<ffffffff814649fe>] driver_attach+0x1e/0x20
 [<ffffffff814645b0>] bus_add_driver+0x180/0x250
 [<ffffffffa014c000>] ? 0xffffffffa014bfff
 [<ffffffff81465a14>] driver_register+0x64/0xf0
 [<ffffffffa014c000>] ? 0xffffffffa014bfff
 [<ffffffff813945cc>] __pci_register_driver+0x4c/0x50
 [<ffffffffa002a35a>] drm_pci_init+0x11a/0x130 [drm]
 [<ffffffffa014c000>] ? 0xffffffffa014bfff
 [<ffffffffa014c06a>] i915_init+0x6a/0x6c [i915]
 [<ffffffff8100216a>] do_one_initcall+0xfa/0x1b0
 [<ffffffff8105a953>] ? set_memory_nx+0x43/0x50
 [<ffffffff811059ed>] load_module+0x1e2d/0x25c0
 [<ffffffff81101070>] ? store_uevent+0x70/0x70
 [<ffffffff811ef5a0>] ? kernel_read+0x50/0x80
 [<ffffffff81106336>] SyS_finit_module+0xa6/0xd0
 [<ffffffff816ff569>] system_call_fastpath+0x16/0x1b