Additional info:
reporter:       libreport-2.2.1
WARNING: CPU: 4 PID: 12784 at drivers/gpu/drm/drm_crtc.c:2051 drm_mode_set_config_internal+0xd6/0xe0 [drm]()
Modules linked in: fuse ip6t_rpfilter bnep bluetooth ip6t_REJECT xt_conntrack cfg80211 rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw snd_hda_codec_hdmi snd_hda_codec_realtek dcdbas iTCO_wdt iTCO_vendor_support x86_pkg_temp_thermal coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul crc32c_intel snd_hda_intel ghash_clmulni_intel snd_hda_codec snd_hwdep microcode snd_seq sb_edac serio_raw edac_core snd_seq_device snd_pcm i2c_i801 e1000e snd_page_alloc snd_timer lpc_ich snd mei_me mei ptp shpchp mfd_core pps_core soundcore binfmt_misc radeon i2c_algo_bit drm_kms_helper ttm isci drm libsas scsi_transport_sas i2c_core
CPU: 4 PID: 12784 Comm: Xorg Not tainted 3.13.6-200.fc20.x86_64 #1
Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A07 11/08/2012
 0000000000000009 ffff8807fb649ab8 ffffffff8168730c 0000000000000000
 ffff8807fb649af0 ffffffff8106d47d ffff880820683aa0 0000000000000000
 ffff880820006000 ffff88082068b860 0000000000000080 ffff8807fb649b00
Call Trace:
 [<ffffffff8168730c>] dump_stack+0x45/0x56
 [<ffffffff8106d47d>] warn_slowpath_common+0x7d/0xa0
 [<ffffffff8106d55a>] warn_slowpath_null+0x1a/0x20
 [<ffffffffa004bad6>] drm_mode_set_config_internal+0xd6/0xe0 [drm]
 [<ffffffffa00d3f41>] drm_fb_helper_set_par+0x71/0xf0 [drm_kms_helper]
 [<ffffffff8136dd41>] fb_set_var+0x191/0x430
 [<ffffffff8109be3d>] ? ttwu_do_activate.constprop.85+0x5d/0x70
 [<ffffffff810a64f7>] ? update_curr+0x67/0x160
 [<ffffffff813794d1>] fbcon_blank+0x1d1/0x2d0
 [<ffffffff813ed348>] do_unblank_screen+0xb8/0x1f0
 [<ffffffff813e319a>] complete_change_console+0x5a/0xe0
 [<ffffffff813e41ce>] vt_ioctl+0xfae/0x1160
 [<ffffffff813d7fad>] tty_ioctl+0x26d/0xb60
 [<ffffffff81691a34>] ? __do_page_fault+0x1f4/0x530
 [<ffffffff811cb758>] do_vfs_ioctl+0x2d8/0x4a0
 [<ffffffff811cb9a1>] SyS_ioctl+0x81/0xa0
 [<ffffffff81691d7e>] ? do_page_fault+0xe/0x10
 [<ffffffff816962e9>] system_call_fastpath+0x16/0x1b

Potential duplicate: bug 1046732