Additional info:
reporter:       libreport-2.2.3
WARNING: CPU: 1 PID: 250 at drivers/gpu/drm/i915/intel_panel.c:683 i9xx_enable_backlight+0xd4/0x100 [i915]()
backlight already enabled
Modules linked in: i915(+) ata_generic i2c_algo_bit yenta_socket firewire_ohci pata_acpi e1000e drm_kms_helper firewire_core crc_itu_t drm ptp i2c_core pps_core video
CPU: 1 PID: 250 Comm: systemd-udevd Not tainted 3.15.10-201.fc20.i686 #1
Hardware name: LENOVO 17025JU/17025JU, BIOS 7BETD8WW (2.19 ) 03/31/2011
 c0c6f907 5cd71141 00000000 f6aa96e4 c09ec0ff f6aa9724 f6aa9714 c044cece
 f853c054 f6aa9744 000000fa f8535ca0 000002ab f8512424 f8512424 f643c000
 f6a24400 f6aad000 f6aa9730 c044cf2e 00000009 f6aa9724 f853c054 f6aa9744
Call Trace:
 [<c09ec0ff>] dump_stack+0x41/0x52
 [<c044cece>] warn_slowpath_common+0x7e/0xa0
 [<f8512424>] ? i9xx_enable_backlight+0xd4/0x100 [i915]
 [<f8512424>] ? i9xx_enable_backlight+0xd4/0x100 [i915]
 [<c044cf2e>] warn_slowpath_fmt+0x3e/0x60
 [<f8512424>] i9xx_enable_backlight+0xd4/0x100 [i915]
 [<f8513557>] intel_panel_enable_backlight+0x77/0xc0 [i915]
 [<f85115b3>] intel_enable_lvds+0x123/0x170 [i915]
 [<f84ed325>] i9xx_crtc_enable+0x285/0x390 [i915]
 [<f84efb56>] __intel_set_mode+0x706/0x1460 [i915]
 [<f84f2f03>] intel_set_mode+0x23/0x40 [i915]
 [<f84f3c04>] intel_crtc_set_config+0x7c4/0xbb0 [i915]
 [<c06a835e>] ? ida_get_new_above+0x1be/0x210
 [<f834e83e>] drm_mode_set_config_internal+0x4e/0xc0 [drm]
 [<f84e67d0>] ? intel_unpin_work_fn+0x100/0x100 [i915]
 [<f81912ea>] drm_fb_helper_restore_fbdev_mode+0xaa/0xe0 [drm_kms_helper]
 [<f8192bde>] drm_fb_helper_set_par+0x2e/0x80 [drm_kms_helper]
 [<c0705142>] fbcon_init+0x482/0x4d0
 [<c076a76e>] visual_init+0x9e/0x100
 [<c076ca6a>] do_bind_con_driver+0x10a/0x2c0
 [<c05d143c>] ? sysfs_create_file_ns+0x2c/0x30
 [<c076d12d>] do_take_over_console+0xfd/0x190
 [<c070086f>] do_fbcon_takeover+0x5f/0xc0
 [<c0705adf>] fbcon_event_notify+0x5ff/0x740
 [<c09f6071>] notifier_call_chain+0x41/0x60
 [<c046f1fb>] __blocking_notifier_call_chain+0x3b/0x60
 [<c046f23f>] blocking_notifier_call_chain+0x1f/0x30
 [<c070b1d6>] fb_notifier_call_chain+0x16/0x20
 [<c070cc5a>] register_framebuffer+0x1ca/0x300
 [<f8192f14>] drm_fb_helper_initial_config+0x2e4/0x13d0 [drm_kms_helper]
 [<f84db089>] ? gen4_write32+0x49/0xc0 [i915]
 [<f84db37f>] ? gen4_read32+0x3f/0xc0 [i915]
 [<f84fdbe3>] ? intel_fbdev_init+0x193/0x510 [i915]
 [<f84fdf7c>] intel_fbdev_initial_config+0x1c/0x20 [i915]
 [<f851cddd>] i915_driver_load+0xd5d/0xdd0 [i915]
 [<f8519e90>] ? i915_switcheroo_set_state+0xa0/0xa0 [i915]
 [<c06a9d9a>] ? kobject_uevent_env+0x15a/0x690
 [<c06a99b0>] ? cleanup_uevent_env+0x10/0x10
 [<c05d15a3>] ? sysfs_add_file+0x23/0x30