On both v3.13-rc1 and v3.13-rc2 is see this at every boot and during every suspend and resume cycle:
<4>[ 2.682468] WARNING: CPU: 0 PID: 173 at drivers/gpu/drm/i915/intel_display.c:9948 intel_get_pipe_from_connector+0x42/0x50 [i915]() <5>[ 2.682470] Modules linked in: i915(F+) ata_generic(F) pata_acpi(F) yenta_socket(F+) i2c_algo_bit(F) drm_kms_helper(F) tg3(F+) ptp(F) pps_core(F) drm(F) i2c_core(F) video(F) sunrpc(F) <5>[ 2.682489] CPU: 0 PID: 173 Comm: systemd-udevd Tainted: GF 3.13.0-0.rc2.1.local0.fc18.i686 #1 <5>[ 2.682492] Hardware name: IBM 2525FAG/2525FAG, BIOS 74ET61WW (2.06 ) 03/14/2006 <5>[ 2.682495] 00000000 00000000 f54739f4 c09b66d2 00000000 f5473a24 c0449b14 c0b541a4 <5>[ 2.682502] 00000000 000000ad f82c9524 000026dc f8282692 f8282692 f555ed80 00061200 <5>[ 2.682509] f567c000 f5473a34 c0449b52 00000009 00000000 f5473a40 f8282692 f5578800 <5>[ 2.682516] Call Trace: <5>[ 2.682528] [<c09b66d2>] dump_stack+0x41/0x52 <5>[ 2.682534] [<c0449b14>] warn_slowpath_common+0x84/0xa0 <5>[ 2.682571] [<f8282692>] ? intel_get_pipe_from_connector+0x42/0x50 [i915] <5>[ 2.682607] [<f8282692>] ? intel_get_pipe_from_connector+0x42/0x50 [i915] <5>[ 2.682612] [<c0449b52>] warn_slowpath_null+0x22/0x30 <5>[ 2.682648] [<f8282692>] intel_get_pipe_from_connector+0x42/0x50 [i915] <5>[ 2.682689] [<f829b161>] intel_panel_disable_backlight+0x21/0x160 [i915] <5>[ 2.682725] [<f8287041>] intel_disable_lvds+0x41/0x160 [i915] <5>[ 2.682760] [<f8278530>] i9xx_crtc_disable+0x200/0x2c0 [i915] <5>[ 2.682802] [<f82b3951>] ? gen4_read32+0x31/0x90 [i915] <5>[ 2.682839] [<f8284aae>] intel_modeset_setup_hw_state+0x92e/0xb00 [i915] <5>[ 2.682844] [<c09b3e00>] ? power_down+0x8c/0x8d <5>[ 2.682884] [<f82b3bb0>] ? gen4_write64+0xa0/0xa0 [i915] <5>[ 2.682920] [<f8284ca0>] intel_modeset_gem_init+0x20/0x30 [i915] <5>[ 2.682950] [<f824ab73>] i915_driver_load+0xb53/0xdd0 [i915] <5>[ 2.682978] [<f8248270>] ? i915_switcheroo_set_state+0xa0/0xa0 [i915] <5>[ 2.683003] [<f80c4d5c>] drm_dev_register+0x8c/0x1a0 [drm] <5>[ 2.683043] [<f80c6895>] drm_get_pci_dev+0x85/0x130 [drm] <5>[ 2.683050] [<c05be578>] ? sysfs_do_create_link_sd.isra.3+0xa8/0x1c0 <5>[ 2.683057] [<c09bffc3>] ? notifier_call_chain+0x43/0x60 <5>[ 2.683086] [<f82474aa>] i915_pci_probe+0x3a/0x80 [i915] <5>[ 2.683093] [<c06cc8d9>] pci_device_probe+0x79/0xc0 <5>[ 2.683097] [<c05be6b5>] ? sysfs_create_link+0x25/0x40 <5>[ 2.683104] [<c077d9b9>] driver_probe_device+0x79/0x360 <5>[ 2.683108] [<c06cc81e>] ? pci_match_device+0x9e/0xb0 <5>[ 2.683113] [<c077dd31>] __driver_attach+0x91/0xa0 <5>[ 2.683117] [<c077dca0>] ? driver_probe_device+0x360/0x360 <5>[ 2.683121] [<c077bf52>] bus_for_each_dev+0x42/0x80 <5>[ 2.683125] [<c077d3ce>] driver_attach+0x1e/0x20 <5>[ 2.683130] [<c077dca0>] ? driver_probe_device+0x360/0x360 <5>[ 2.683134] [<c077d07c>] bus_add_driver+0xec/0x210 <5>[ 2.683138] [<c077e349>] driver_register+0x59/0xe0 <5>[ 2.683142] [<f7fb2000>] ? 0xf7fb1fff <5>[ 2.683147] [<c06cba63>] __pci_register_driver+0x33/0x40 <5>[ 2.683150] [<f7fb2000>] ? 0xf7fb1fff <5>[ 2.683166] [<f80c6a3d>] drm_pci_init+0xfd/0x110 [drm] <5>[ 2.683170] [<f7fb2000>] ? 0xf7fb1fff <5>[ 2.683198] [<f7fb205e>] i915_init+0x5e/0x60 [i915] <5>[ 2.683203] [<c040049a>] do_one_initcall+0xda/0x1a0 <5>[ 2.683206] [<f7fb2000>] ? 0xf7fb1fff <5>[ 2.683211] [<c04eff41>] ? __add_event_to_tracers+0x21/0x30 <5>[ 2.683215] [<f7fb2000>] ? 0xf7fb1fff <5>[ 2.683221] [<c043dff7>] ? set_memory_ro+0x37/0x40 <5>[ 2.683228] [<c04b15ad>] load_module+0x1abd/0x2390 <5>[ 2.683235] [<c04b1f27>] SyS_init_module+0xa7/0x110 <5>[ 2.683242] [<c052214b>] ? vm_mmap_pgoff+0x8b/0xb0 <5>[ 2.683248] [<c09c3a0d>] sysenter_do_call+0x12/0x28
Feel free to prod for further details.
Paul Bolle