gpe16 interrupt using > 90% cpu in gmux_index_wait_ready.isra

[Joe Barnett]

on a retina macbook pro (MacBookPro11,3), I recently* noticed >90% of cpu being used in kworker thread, similar to http://askubuntu.com/questions/444005/what-is-causing-ubuntu-on-macbook-pro-to-have-high-cpu-usage

disabling the gpe16 interrupt restores cpu idleness, and the stack trace shows:

# cat /proc/4/stack
[<ffffffffa00f0077>] gmux_index_wait_ready.isra.7+0x47/0x70 [apple_gmux]
[<ffffffffa00f0159>] gmux_index_write8+0x39/0x60 [apple_gmux]
[<ffffffffa00f0e05>] gmux_notify_handler+0xd5/0x119 [apple_gmux]
[<ffffffff813fba01>] acpi_ev_notify_dispatch+0x44/0x5c
[<ffffffff813e86f8>] acpi_os_execute_deferred+0x14/0x20
[<ffffffff810838a2>] process_one_work+0x182/0x450
[<ffffffff81084641>] worker_thread+0x121/0x410
[<ffffffff8108b312>] kthread+0xd2/0xf0
[<ffffffff8172a2fc>] ret_from_fork+0x7c/0xb0
[<ffffffffffffffff>] 0xffffffffffffffff

*"recently" being yesterday, when I started plugging in an external monitor via mindisplayport/thunderbolt port, and also started using the 3.13.0-27-generic kernel image

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-27-generic 3.13.0-27.50
ProcVersionSignature: Ubuntu 3.13.0-27.50-generic 3.13.11
Uname: Linux 3.13.0-27-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC2: jbarnett 2982 F.... pulseaudio
 /dev/snd/controlC0: jbarnett 2982 F.... pulseaudio
 /dev/snd/controlC1: jbarnett 2982 F.... pulseaudio
CurrentDesktop: GNOME
Date: Wed May 21 09:25:40 2014
HibernationDevice: RESUME=UUID=948280a0-a059-468d-8484-f0d317f46e6d
InstallationDate: Installed on 2014-02-24 (85 days ago)
InstallationMedia: Ubuntu-GNOME 14.04 "Trusty Tahr" - Alpha amd64 (20140218)
MachineType: Apple Inc. MacBookPro11,3
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-27-generic.efi.signed root=UUID=135fd833-3282-4f3b-8802-0a27ec2765b9 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-27-generic N/A
 linux-backports-modules-3.13.0-27-generic N/A
 linux-firmware 1.127.2
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/18/2013
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP112.88Z.0138.B02.1310181745
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-2BD1B31983FE1663
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro11,3
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-2BD1B31983FE1663
dmi.modalias: dmi:bvnAppleInc.:bvrMBP112.88Z.0138.B02.1310181745:bd10/18/2013:svnAppleInc.:pnMacBookPro11,3:pvr1.0:rvnAppleInc.:rnMac-2BD1B31983FE1663:rvrMacBookPro11,3:cvnAppleInc.:ct10:cvrMac-2BD1B31983FE1663:
dmi.product.name: MacBookPro11,3
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.15 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'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-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/v3.15-rc5-utopic/

[Joe Barnett (thejoe)]

still happens in latest

[Joe Barnett (thejoe)]

also, sleep & resume seems to allow me to re-enable gpe16 without seeing the cpu utilization

[Eric Wilkison (ericw-j)]

Still seeing this on a new install of Vivid (Gnome Edition) with kernel 3.19..0-25. I am also running on a MacBook Pro and using external monitors via thunderbolt ports. A sleep/resume cycle after reboot removes the symptom as well.