Comment 12 for bug 1351353

kernel 4.4, ubuntu 16.04 (4.4.0-20-generic and -21), TOSHIBA PORTEGE Z30-B
evertytime when external lcd is connected via hdmi

[ 104.875123] ------------[ cut here ]------------
[ 104.875146] WARNING: CPU: 2 PID: 1425 at /build/linux-yplzxd/linux-4.4.0/drivers/gpu/drm/i915/intel_display.c:3968 intel_crtc_wait_for_pending_flips+0x233/0x240 [i915]()
[ 104.875147] Removing stuck page flip
[ 104.875147] Modules linked in: nvram msr drbg ansi_cprng ctr ccm ebtable_filter ebtables ip6table_filter ip6_tables rfcomm iptable_filter ip_tables x_tables binfmt_misc pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) bnep uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core v4l2_common videodev media btusb btrtl btbcm btintel bluetooth snd_hda_codec_hdmi joydev arc4 intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel nls_iso8859_1 kvm irqbypass crct10dif_pclmul crc32_pclmul aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper iwlmvm cryptd mac80211 snd_soc_rt5640 snd_hda_codec_realtek snd_hda_codec_generic snd_soc_rl6231 iwlwifi snd_soc_core input_leds snd_compress ac97_bus serio_raw cfg80211 snd_pcm_dmaengine rtsx_pci_ms snd_hda_intel lpc_ich
[ 104.875175] snd_hda_codec memstick snd_hda_core snd_hwdep snd_seq_midi snd_pcm snd_seq_midi_event shpchp mei_me toshiba_acpi snd_rawmidi mei sparse_keymap toshiba_haps snd_seq toshiba_bluetooth snd_seq_device snd_timer snd soundcore dw_dmac dw_dmac_core tpm_infineon i2c_designware_platform 8250_dw spi_pxa2xx_platform i2c_designware_core snd_soc_sst_acpi mac_hid parport_pc ppdev lp parport autofs4 rtsx_pci_sdmmc i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect ahci e1000e psmouse sysimgblt fb_sys_fops ptp drm libahci rtsx_pci pps_core wmi fjes sdhci_acpi video sdhci
[ 104.875197] CPU: 2 PID: 1425 Comm: Xorg Tainted: G W OE 4.4.0-22-generic #38-Ubuntu
[ 104.875198] Hardware name: TOSHIBA PORTEGE Z30-B/PORTEGE Z30-B, BIOS Version 2.10 01/06/2015
[ 104.875199] 0000000000000086 000000003d06b92c ffff88040a4f3ad0 ffffffff813e9c73
[ 104.875201] ffff88040a4f3b18 ffffffffc02a3a50 ffff88040a4f3b08 ffffffff81080fb2
[ 104.875203] ffff88040ebdd1a8 ffff880408069008 ffff88040deb9000 ffff88040ebdd000
[ 104.875205] Call Trace:
[ 104.875208] [<ffffffff813e9c73>] dump_stack+0x63/0x90
[ 104.875211] [<ffffffff81080fb2>] warn_slowpath_common+0x82/0xc0
[ 104.875213] [<ffffffff8108104c>] warn_slowpath_fmt+0x5c/0x80
[ 104.875216] [<ffffffff810c35d5>] ? finish_wait+0x55/0x70
[ 104.875237] [<ffffffffc023e073>] intel_crtc_wait_for_pending_flips+0x233/0x240 [i915]
[ 104.875240] [<ffffffff810c3a70>] ? wake_atomic_t_function+0x60/0x60
[ 104.875261] [<ffffffffc023f291>] intel_pre_plane_update+0x111/0x140 [i915]
[ 104.875282] [<ffffffffc023f800>] intel_atomic_commit+0xf0/0x6f0 [i915]
[ 104.875297] [<ffffffffc009280e>] ? drm_atomic_check_only+0x18e/0x590 [drm]
[ 104.875311] [<ffffffffc0091d1d>] ? drm_atomic_set_crtc_for_connector+0x3d/0xe0 [drm]
[ 104.875324] [<ffffffffc0092c47>] drm_atomic_commit+0x37/0x60 [drm]
[ 104.875331] [<ffffffffc01989f6>] drm_atomic_helper_set_config+0x76/0xb0 [drm_kms_helper]
[ 104.875345] [<ffffffffc009146a>] ? drm_modeset_lock_all_ctx+0x9a/0xb0 [drm]
[ 104.875357] [<ffffffffc0081e02>] drm_mode_set_config_internal+0x62/0x100 [drm]
[ 104.875369] [<ffffffffc0086322>] drm_mode_setcrtc+0x3d2/0x4f0 [drm]
[ 104.875378] [<ffffffffc0077712>] drm_ioctl+0x152/0x540 [drm]
[ 104.875390] [<ffffffffc0085f50>] ? drm_mode_setplane+0x1b0/0x1b0 [drm]
[ 104.875393] [<ffffffff8122028f>] do_vfs_ioctl+0x29f/0x490
[ 104.875395] [<ffffffff817002c0>] ? __sys_recvmsg+0x80/0x90
[ 104.875397] [<ffffffff812204f9>] SyS_ioctl+0x79/0x90
[ 104.875400] [<ffffffff818252f2>] entry_SYSCALL_64_fastpath+0x16/0x71
[ 104.875402] ---[ end trace 655856c2a15a2037 ]---