I've also tested this on 4.4.0-22 with i915 patches here: http://koti.kapsi.fi/~tjaalton/skl/mst/ And the problem persists.
In addition I've tested a 4.6 mainline from 5/8 and the problem persists there as well. Here is the warning from the mainline kernel: [ 44.871672] ------------[ cut here ]------------ [ 44.871687] WARNING: CPU: 1 PID: 871 at /home/kernel/COD/linux/drivers/gpu/drm/i915/intel_pm.c:3586 skl_update_other_pipe_wm+0x16c/0x180 [i915] [ 44.871688] WARN_ON(!wm_changed) [ 44.871688] Modules linked in: [ 44.871689] rfcomm bnep snd_hda_codec_hdmi dell_led brcmfmac snd_hda_codec_realtek intel_rapl snd_hda_codec_generic x86_pkg_temp_thermal intel_powerclamp brcmutil coretemp uvcvideo cfg80211 i2c_designware_platform i2c_designware_core kvm_intel videobuf2_vmalloc kvm snd_hda_intel videobuf2_memops snd_hda_codec videobuf2_v4l2 dell_wmi dell_laptop videobuf2_core dell_smbios snd_hda_core videodev dcdbas rtsx_pci_ms irqbypass snd_hwdep media memstick snd_pcm hid_multitouch crct10dif_pclmul snd_seq_midi crc32_pclmul btusb btrtl ghash_clmulni_intel snd_seq_midi_event snd_rawmidi aesni_intel snd_seq snd_seq_device aes_x86_64 lrw snd_timer gf128mul glue_helper snd ablk_helper cryptd soundcore hci_uart btbcm btqca idma64 joydev input_leds shpchp btintel virt_dma mei_me serio_raw bluetooth mei processor_thermal_device [ 44.871711] intel_lpss_pci intel_soc_dts_iosf acpi_als kfifo_buf industrialio intel_lpss_acpi intel_hid dell_smo8800 int3403_thermal int3400_thermal int3402_thermal intel_lpss acpi_pad sparse_keymap int340x_thermal_zone acpi_thermal_rel mac_hid parport_pc ppdev lp parport autofs4 usbhid rtsx_pci_sdmmc nouveau i915 mxm_wmi ttm i2c_algo_bit drm_kms_helper psmouse syscopyarea sysfillrect sysimgblt nvme fb_sys_fops uas nvme_core ahci drm usb_storage rtsx_pci libahci i2c_hid hid wmi pinctrl_sunrisepoint video pinctrl_intel fjes [ 44.871727] CPU: 1 PID: 871 Comm: Xorg Not tainted 4.6.0-999-generic #201605082200 [ 44.871728] Hardware name: Dell Inc. XPS 15 9550/0N7TVV, BIOS 01.02.00 04/07/2016 [ 44.871729] 0000000000000286 0000000052e51aba ffff8808985bf918 ffffffff813f2ea3 [ 44.871731] ffff8808985bf968 0000000000000000 ffff8808985bf958 ffffffff8108294b [ 44.871732] 00000e0200000000 ffff880891b41000 ffff8800219d9da4 ffff880891b42000 [ 44.871733] Call Trace: [ 44.871736] [<ffffffff813f2ea3>] dump_stack+0x63/0x90 [ 44.871739] [<ffffffff8108294b>] __warn+0xcb/0xf0 [ 44.871740] [<ffffffff810829cf>] warn_slowpath_fmt+0x5f/0x80 [ 44.871749] [<ffffffffc022c6ac>] skl_update_other_pipe_wm+0x16c/0x180 [i915] [ 44.871758] [<ffffffffc022c845>] skl_update_wm+0x185/0x640 [i915] [ 44.871769] [<ffffffffc027a455>] ? gen9_write32+0x235/0x370 [i915] [ 44.871782] [<ffffffffc02b88af>] ? intel_ddi_enable_transcoder_func+0x17f/0x260 [i915] [ 44.871790] [<ffffffffc023060e>] intel_update_watermarks+0x1e/0x30 [i915] [ 44.871802] [<ffffffffc029c821>] haswell_crtc_enable+0x321/0x8c0 [i915] [ 44.871813] [<ffffffffc02991bb>] intel_atomic_commit+0x5fb/0xdd0 [i915] [ 44.871825] [<ffffffffc00d9c31>] ? drm_atomic_check_only+0x181/0x600 [drm] [ 44.871832] [<ffffffffc00da0e7>] drm_atomic_commit+0x37/0x60 [drm] [ 44.871837] [<ffffffffc019b03a>] drm_atomic_helper_set_config+0x7a/0xb0 [drm_kms_helper] [ 44.871844] [<ffffffffc00c9b42>] drm_mode_set_config_internal+0x62/0x100 [drm] [ 44.871851] [<ffffffffc00cda90>] drm_mode_setcrtc+0x3e0/0x500 [drm] [ 44.871856] [<ffffffffc00beab2>] drm_ioctl+0x152/0x540 [drm] [ 44.871862] [<ffffffffc00cd6b0>] ? drm_mode_setplane+0x1b0/0x1b0 [drm] [ 44.871864] [<ffffffff81237721>] do_vfs_ioctl+0xa1/0x5b0 [ 44.871866] [<ffffffff81090981>] ? __set_task_blocked+0x41/0xa0 [ 44.871867] [<ffffffff81093306>] ? __set_current_blocked+0x36/0x60 [ 44.871868] [<ffffffff81237ca9>] SyS_ioctl+0x79/0x90 [ 44.871869] [<ffffffff810935ce>] ? SyS_rt_sigprocmask+0x8e/0xc0 [ 44.871872] [<ffffffff81845476>] entry_SYSCALL_64_fastpath+0x1e/0xa8 [ 44.871873] ---[ end trace 12f151afa4c9e462 ]--- [ 53.708328] dell_wmi: Unknown WMI event type 0x12 ** Description changed: - This crash happens when plugging in an external HDMI projector. + This crash happens when plugging in an external HDMI projector in + mirrored mode. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-22-generic 4.4.0-22.39 ProcVersionSignature: Ubuntu 4.4.0-22.39-generic 4.4.8 Uname: Linux 4.4.0-22-generic x86_64 NonfreeKernelModules: zfs zunicode zcommon znvpair zavl ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: mark 4296 F.... pulseaudio Date: Tue May 10 10:25:07 2016 InstallationDate: Installed on 2016-05-02 (8 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 04f3:21d4 Elan Microelectronics Corp. Bus 001 Device 002: ID 0a5c:6410 Broadcom Corp. Bus 001 Device 004: ID 0c45:6713 Microdia Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: Dell Inc. XPS 15 9550 ProcEnviron: LANGUAGE=en_GB:en TERM=linux PATH=(custom, no user) LANG=en_GB.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-22-generic.efi.signed root=UUID=3643ef37-7cee-41b3-9387-2faa819c44db ro quiet splash vt.handoff=7 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: Home directory not accessible: Permission denied No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-4.4.0-22-generic N/A linux-backports-modules-4.4.0-22-generic N/A linux-firmware 1.157 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 04/07/2016 dmi.bios.vendor: Dell Inc. dmi.bios.version: 01.02.00 dmi.board.name: 0N7TVV dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr01.02.00:bd04/07/2016:svnDellInc.:pnXPS159550:pvr:rvnDellInc.:rn0N7TVV:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.name: XPS 15 9550 dmi.sys.vendor: Dell Inc. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1580272 Title: i915-bpo crashes on external hdmi input To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1580272/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs