Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?
Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.6 kernel[0]. If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'. If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'. Once testing of the upstream kernel is complete, please mark this bug as "Confirmed". Thanks in advance. [0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.6-rc4-wily/ ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1568865 Title: [drm:intel_cpu_fifo_underrun_irq_handler [i915_bpo]] *ERROR* CPU pipe B FIFO underrun Status in linux package in Ubuntu: Incomplete Bug description: Running Gnome-Shell on ubuntu 16.04 on my Dell XPS 15 9550 laptop using Intel graphics (Nvidia card turned off), I get this error in syslog when plugging in an external monitor (HDMI). Apr 11 14:28:38 miaco kernel: [ 2616.604641] [drm:intel_cpu_fifo_underrun_irq_handler [i915_bpo]] *ERROR* CPU pipe B FIFO underrun Meanwhile both screens flash and show corruption. Most of the time this has caused a hang that needs a hard power off to get out of, but occasionally removing the external monitor is enough to get going again and so I've been able to find this message in the logs. Note that when using Nvidia (proprietary) drivers and Unity DE I do not have this problem; so it seems to be related to the intel drivers, or possibly Gnome Shell's use of them. Happy to help if I can (would like to be able to use external monitors!) Rich ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-18-generic 4.4.0-18.34 ProcVersionSignature: Ubuntu 4.4.0-18.34-generic 4.4.6 Uname: Linux 4.4.0-18-generic x86_64 ApportVersion: 2.20.1-0ubuntu1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: rich 1943 F.... pulseaudio Date: Mon Apr 11 14:31:26 2016 InstallationDate: Installed on 2016-03-21 (21 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160307) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 04f3:21d5 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=xterm-256color PATH=(custom, no user) LANG=en_GB.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-18-generic.efi.signed root=UUID=3f8391d5-e9cc-4768-8efb-8f04d340567c 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-4.4.0-18-generic N/A linux-backports-modules-4.4.0-18-generic N/A linux-firmware 1.157 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 01/25/2016 dmi.bios.vendor: Dell Inc. dmi.bios.version: 01.01.19 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.:bvr01.01.19:bd01/25/2016:svnDellInc.:pnXPS159550:pvr:rvnDellInc.:rn0N7TVV:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.name: XPS 15 9550 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1568865/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
