I just tried with the Vivid kernel (3.18.0) and had the same error. I needed to restart lightdm to get things going again.
[ 65.108123] WARNING: CPU: 0 PID: 6 at /build/buildd/linux-3.18.0/drivers/gpu/drm/i915/intel_display.c:5158 intel_modeset_check_state+0x6cd/0 x770 [i915]() [ 65.108125] active connector not linked to encoder [ 65.108171] Modules linked in: arc4 btusb gpio_ich snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer ath5k ath joydev snd mac80211 pcmcia serio_raw rfcomm bnep bluetooth i915 yenta_socket pcmcia_rsrc cfg80211 so undcore lpc_ich toshiba_acpi pcmcia_core sparse_keymap toshiba_bluetooth binfmt_misc drm_kms_helper wmi toshiba_haps tpm_infineon drm mac_hid v ideo shpchp i2c_algo_bit parport_pc ppdev lp parport pata_acpi sdhci_pci psmouse sdhci sky2 [ 65.108176] CPU: 0 PID: 6 Comm: kworker/u2:0 Tainted: G W 3.18.0-9-generic #10-Ubuntu [ 65.108178] Hardware name: TOSHIBA PORTEGE R200/Portable PC, BIOS Version 1.60 10/25/2005 [ 65.108188] Workqueue: events_unbound async_run_entry_fn [ 65.108195] 00000000 00000000 f50abd28 c16d31b6 f50abd6c f50abd5c c105fb32 f89a7ec4 [ 65.108202] f50abd88 00000006 f89a5a10 00001426 f895d0ed 00001426 f895d0ed f331ec00 [ 65.108208] f2936dc8 f294b300 f50abd74 c105fb83 00000009 f50abd6c f89a7ec4 f50abd88 [ 65.108209] Call Trace: [ 65.108217] [<c16d31b6>] dump_stack+0x41/0x52 [ 65.108223] [<c105fb32>] warn_slowpath_common+0x82/0xa0 [ 65.108272] [<f895d0ed>] ? intel_modeset_check_state+0x6cd/0x770 [i915] [ 65.108318] [<f895d0ed>] ? intel_modeset_check_state+0x6cd/0x770 [i915] [ 65.108323] [<c105fb83>] warn_slowpath_fmt+0x33/0x40 [ 65.108370] [<f895d0ed>] intel_modeset_check_state+0x6cd/0x770 [i915] [ 65.108419] [<f895edff>] intel_modeset_setup_hw_state+0x76f/0xbe0 [i915] [ 65.108457] [<f863e1f0>] ? drm_modeset_lock+0x30/0xf0 [drm] [ 65.108501] [<f89403c0>] ? gen4_read16+0xc0/0xc0 [i915] [ 65.108531] [<f88fd108>] __i915_drm_thaw+0x108/0x170 [i915] [ 65.108562] [<f88fdba3>] i915_resume+0x23/0x40 [i915] [ 65.108593] [<f88fdbd0>] i915_pm_resume+0x10/0x20 [i915] [ 65.108598] [<c138171f>] pci_pm_resume+0x4f/0x90 [ 65.108605] [<c14693b6>] dpm_run_callback+0x46/0x100 [ 65.108609] [<c13816d0>] ? pci_pm_thaw+0x90/0x90 [ 65.108613] [<c146988d>] device_resume+0xad/0x1a0 [ 65.108617] [<c146999e>] async_resume+0x1e/0x50 [ 65.108621] [<c107ddce>] async_run_entry_fn+0x4e/0x170 [ 65.108626] [<c10875bf>] ? wake_up_process+0x1f/0x40 [ 65.108631] [<c1076932>] process_one_work+0x122/0x3e0 [ 65.108635] [<c1076c31>] worker_thread+0x41/0x560 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1384297 Title: After system resume, Intel i915 graphics hangs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1384297/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs