Description of problem:
plugging and unplugging a Dell 27" TFT monitor attached via DisplayPort

Additional info:
reporter:       libreport-2.1.12
WARNING: CPU: 2 PID: 1001 at drivers/gpu/drm/i915/intel_dp.c:2538 intel_dp_link_down+0x1dc/0x210 [i915]()
Modules linked in: rfcomm fuse ip6t_rpfilter ip6t_REJECT xt_conntrack 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 bnep iTCO_wdt iTCO_vendor_support arc4 iwldvm x86_pkg_temp_thermal coretemp mac80211 kvm_intel kvm snd_hda_codec_hdmi microcode iwlwifi snd_hda_codec_realtek serio_raw snd_usb_audio cfg80211 uvcvideo videobuf2_vmalloc udl snd_usbmidi_lib asix drm_usb videobuf2_memops joydev btusb snd_rawmidi bluetooth sdhci_pci snd_hda_intel videobuf2_core cdc_mbim ax88179_178a videodev sdhci snd_hda_codec media mmc_core snd_hwdep snd_seq cdc_wdm snd_seq_device cdc_ncm usbnet snd_pcm cdc_acm mii lpc_ich shpchp mfd_core snd_page_alloc i2c_i801 snd_timer mei_me mei wmi thinkpad_acpi snd tpm_tis soundcore tpm rfkill tpm_bios dm_crypt crct10dif_pclmul crc32_pclmul crc32c_intel i915 i2c_algo_bit ghash_clmulni_intel drm_kms_helper drm i2c_core video
CPU: 2 PID: 1001 Comm: Xorg Not tainted 3.12.9-301.fc20.x86_64 #1
Hardware name: LENOVO 34602SG/34602SG, BIOS G6ET96WW (2.56 ) 04/29/2013
 0000000000000009 ffff880210601c00 ffffffff81667af7 0000000000000000
 ffff880210601c38 ffffffff8106918d ffff880036dee0c8 ffff88020fc95800
 ffff880212f77000 0000000080180344 ffff88020f93c000 ffff880210601c48
Call Trace:
 [<ffffffff81667af7>] dump_stack+0x45/0x56
 [<ffffffff8106918d>] warn_slowpath_common+0x7d/0xa0
 [<ffffffff8106926a>] warn_slowpath_null+0x1a/0x20
 [<ffffffffa00d63ac>] intel_dp_link_down+0x1dc/0x210 [i915]
 [<ffffffffa00d8d68>] intel_disable_dp+0x68/0x70 [i915]
 [<ffffffffa00c300a>] ironlake_crtc_disable+0x19a/0x950 [i915]
 [<ffffffffa00c737f>] intel_crtc_update_dpms+0x6f/0xa0 [i915]
 [<ffffffffa00cacc9>] intel_connector_dpms+0x59/0x70 [i915]
 [<ffffffffa0031778>] drm_mode_obj_set_property_ioctl+0x308/0x320 [drm]
 [<ffffffffa00317c0>] drm_mode_connector_property_set_ioctl+0x30/0x40 [drm]
 [<ffffffffa0020c32>] drm_ioctl+0x502/0x630 [drm]
 [<ffffffff811c111d>] do_vfs_ioctl+0x2dd/0x4b0
 [<ffffffff811c1371>] SyS_ioctl+0x81/0xa0
 [<ffffffff81676aa9>] system_call_fastpath+0x16/0x1b