Control variate:

still getting this on the latest 4.2 mainline kernel

[   24.358337] ------------[ cut here ]------------
[   24.358356] WARNING: CPU: 2 PID: 1026 at /home/kernel/COD/linux/drivers/gpu/drm/i915/intel_display.c:1362 assert_plane.constprop.94+0x73/0xa0 [i915]()
[   24.358356] plane A assertion failure (expected on, current off)
[   24.358375] Modules linked in: xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables cmac rfcomm bnep nls_iso8859_1 uas usb_storage arc4 intel_rapl iosf_mbi x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel iwlmvm uvcvideo aesni_intel aes_x86_64 lrw mac80211 gf128mul glue_helper ablk_helper cryptd snd_usb_audio videobuf2_vmalloc snd_usbmidi_lib serio_raw snd_seq_midi snd_seq_midi_event videobuf2_memops videobuf2_core v4l2_common snd_rawmidi snd_hda_codec_hdmi iwlwifi snd_hda_codec_realtek videodev snd_hda_codec_generic
[   24.358395]  btusb snd_seq btrtl media joydev btbcm btintel cfg80211 input_leds bluetooth mei_me snd_hda_intel mei snd_hda_codec lpc_ich snd_soc_rt5640 snd_hda_core snd_soc_rl6231 shpchp snd_hwdep snd_soc_core snd_compress ac97_bus nuvoton_cir snd_pcm_dmaengine rc_core snd_pcm snd_soc_sst_acpi snd_seq_device snd_timer i2c_hid acpi_pad dw_dmac snd dw_dmac_core 8250_dw i2c_designware_platform i2c_designware_core spi_pxa2xx_platform soundcore mac_hid acpi_als kfifo_buf industrialio parport_pc ppdev sunrpc lp parport autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear hid_generic usbhid hid i915 i2c_algo_bit drm_kms_helper psmouse e1000e drm ahci ptp libahci pps_core sdhci_acpi video sdhci
[   24.358397] CPU: 2 PID: 1026 Comm: Xorg Not tainted 4.2.0-040200rc8-generic #201508240030
[   24.358397] Hardware name: \xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff \xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff/NUC5i7RYB, BIOS RYBDWi35.86A.0246.2015.0309.1355 03/09/2015
[   24.358399]  ffffffffc025bc70 ffff8804084bf7b8 ffffffff817a1aa3 0000000000000001
[   24.358400]  ffff8804084bf808 ffff8804084bf7f8 ffffffff8107719a ffff880035df0000
[   24.358401]  0000000000000000 ffff880035df0000 ffff8804072e3000 ffff8804072e3060
[   24.358401] Call Trace:
[   24.358404]  [<ffffffff817a1aa3>] dump_stack+0x45/0x57
[   24.358406]  [<ffffffff8107719a>] warn_slowpath_common+0x8a/0xc0
[   24.358408]  [<ffffffff81077216>] warn_slowpath_fmt+0x46/0x50
[   24.358418]  [<ffffffffc01f29e3>] assert_plane.constprop.94+0x73/0xa0 [i915]
[   24.358427]  [<ffffffffc01fc9e1>] hsw_disable_ips+0x41/0x180 [i915]
[   24.358436]  [<ffffffffc01fcb7d>] intel_pre_disable_primary+0x5d/0x90 [i915]
[   24.358444]  [<ffffffffc01fcbf8>] intel_crtc_disable_planes+0x48/0x110 [i915]
[   24.358452]  [<ffffffffc01fd541>] __intel_set_mode+0x251/0xb10 [i915]
[   24.358460]  [<ffffffffc01ff0b2>] ? intel_modeset_compute_config+0x362/0xb60 [i915]
[   24.358468]  [<ffffffffc0204886>] intel_crtc_set_config+0x366/0x5a0 [i915]
[   24.358477]  [<ffffffffc00803e8>] drm_mode_set_config_internal+0x68/0x100 [drm]
[   24.358482]  [<ffffffffc0168e42>] restore_fbdev_mode+0xc2/0xf0 [drm_kms_helper]
[   24.358484]  [<ffffffffc016ac19>] drm_fb_helper_restore_fbdev_mode_unlocked+0x29/0x70 [drm_kms_helper]
[   24.358486]  [<ffffffffc016ac82>] drm_fb_helper_set_par+0x22/0x40 [drm_kms_helper]
[   24.358495]  [<ffffffffc0211a3a>] intel_fbdev_set_par+0x1a/0x60 [i915]
[   24.358497]  [<ffffffff812bad66>] ? jbd2_journal_dirty_metadata+0xb6/0x250
[   24.358499]  [<ffffffff81413a41>] fb_set_var+0x191/0x400
[   24.358501]  [<ffffffff8129fa01>] ? __ext4_handle_dirty_metadata+0x81/0x210
[   24.358503]  [<ffffffff8140ad9c>] fbcon_blank+0x1bc/0x2b0
[   24.358505]  [<ffffffff8149a3a8>] do_unblank_screen+0xb8/0x1c0
[   24.358507]  [<ffffffff81491883>] vt_ioctl+0x1063/0x10e0
[   24.358508]  [<ffffffff8179e708>] ? __slab_free+0x104/0x25c
[   24.358510]  [<ffffffff81484777>] tty_ioctl+0x1f7/0xbe0
[   24.358512]  [<ffffffff81198671>] ? kzfree+0x31/0x40
[   24.358513]  [<ffffffff811cbc58>] ? kfree+0xf8/0x130
[   24.358515]  [<ffffffff811fc62d>] do_vfs_ioctl+0x2cd/0x4b0
[   24.358517]  [<ffffffff81208df4>] ? mntput+0x24/0x40
[   24.358518]  [<ffffffff811eb4d0>] ? __fput+0x190/0x210
[   24.358519]  [<ffffffff811fc889>] SyS_ioctl+0x79/0x90
[   24.358520]  [<ffffffff817a8db2>] entry_SYSCALL_64_fastpath+0x16/0x75
[   24.358521] ---[ end trace 537139706fa96fdd ]---