Regression: HDMI audio produces no sound (Skylake NUC)

[Joseph Nuzman]

After upgrade from Xenial 16.04 to Yakkety 16.10, playing audio over HDMI no longer produces sound.
* When booting with old kernel from Xenial (4.4.0-59), HDMI audio works fine
* Audio from headphone jack works fine
* Userspace seems to be happily playing to HDMI audio device, but no sound produced at HDMI sink (Samsung TV)

Any of a wide range of pre-built mainline kernels fail to produce HDMI audio, but with a different failure mode (HDMI audio does not seem to be enumerated in the same way as in the Ubuntu kernels.)

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: linux-image-4.8.0-34-generic 4.8.0-34.36
ProcVersionSignature: Ubuntu 4.8.0-34.36-generic 4.8.11
Uname: Linux 4.8.0-34-generic x86_64
ApportVersion: 2.20.3-0ubuntu8.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: israel 1973 F.... pulseaudio
 /dev/snd/controlC1: israel 1973 F.... pulseaudio
CurrentDesktop: Unity
Date: Fri Jan 20 08:58:35 2017
HibernationDevice: RESUME=UUID=ca27f739-071f-4c25-974e-0d0f0614b21c
InstallationDate: Installed on 2016-10-03 (108 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.8.0-34-generic.efi.signed root=UUID=90c3e094-e890-4c35-a0d2-0a358f5d2430 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.8.0-34-generic N/A
 linux-backports-modules-4.8.0-34-generic N/A
 linux-firmware 1.161.1
SourcePackage: linux
UpgradeStatus: Upgraded to yakkety on 2017-01-13 (6 days ago)
dmi.bios.date: 06/03/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: KYSKLi70.86A.0037.2016.0603.1032
dmi.board.name: NUC6i7KYB
dmi.board.vendor: Intel Corporation
dmi.board.version: H90766-405
dmi.chassis.type: 3
dmi.chassis.vendor: Intel Corporation
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrKYSKLi70.86A.0037.2016.0603.1032:bd06/03/2016:svn:pn:pvr:rvnIntelCorporation:rnNUC6i7KYB:rvrH90766-405:cvnIntelCorporation:ct3:cvr1.0:

[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 v4.10 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/v4.10-rc5

[Joseph Salisbury (jsalisbury)]

I'd like to perform a bisect to figure out what commit caused this regression. We need to identify the earliest kernel where the issue started happening as well as the latest kernel that did not have this issue.

Can you test the following kernels and report back? We are looking for the first kernel version that exhibits this bug:

4.5 final: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.5-wily/
4.6 final: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.6-yakkety/
4.7 final: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.7/
4.8-rc1: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.8-rc1/

You don't have to test every kernel, just up until the kernel that first has this bug.

Thanks in advance!

[Joseph Nuzman (jnuzman)]

Kernel behavior summary:

Ubuntu 4.4.0-59: HDMI audio works properly

Mainline 4.4 (any): i915 drm driver does not seem to support Skylake, HDMI audio not enumerated

All of the below kernels exhibit the same problem: HDMI produces no sound
Mainline 4.5rc1
Mainline 4.5 final
Mainline 4.6 final
Mainline 4.7 final
Mainline 4.8 final
Ubuntu 4.8.0-34
Mainline 4.9 final
Mainline 4.10rc5

From here, it's not clear to me how to bisect between the working kernel and any of the not-working kernels without breaking the back-ported i915 driver along the way.

[Joseph Salisbury (jsalisbury)]

Can you test the following two early Yakkety kernels:

4.6.0-10: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/bootstrap/+build/10600030
4.8.0-11: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/unstable/+build/10923199

With these kernels, you need to install both the linux-image and linux-image-extra .deb packages.

[Joseph Nuzman (jnuzman)]

Both kernels behave like any of the kernels from 4.5: no sound on HDMI.

Recapping:

Ubuntu 4.4.0-59: HDMI audio works properly

Mainline 4.4 (any): i915 drm driver does not seem to support Skylake, HDMI audio not enumerated

All of the below kernels exhibit the same problem: HDMI produces no sound
Mainline 4.5rc1
Mainline 4.5 final
Mainline 4.6 final
Ubuntu 4.6.0-10
Mainline 4.7 final
Mainline 4.8 final
Ubuntu 4.8.0-11
Ubuntu 4.8.0-34
Mainline 4.9 final
Mainline 4.10rc5

[Joseph Salisbury (jsalisbury)]

Can you test the 4.4.0-21 kernel next:
https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/9594168

If it is good, we can bisect between 4.4.0-21 and 4.6.0-10.

[Joseph Nuzman (jnuzman)]

Yes, 4.4.0-21 is good, just like 4.4.0-59.

[Joseph Salisbury (jsalisbury)]

I started a kernel bisect between 4.4 final and v4.5-rc1. The kernel bisect will require testing of about 7-10 test kernels.

I built the first test kernel, up to the following commit:
1289ace5b4f70f1e68ce785735b82c7e483de863

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1657994

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[Joseph Nuzman (jnuzman)]

For this kernel, no audio. Failure mode is like 4.4 mainline.

Just to understand: the strategy is to bisect between two mainline kernels with different failure modes (4.4 final and 4.5rc1), with the hope that between the two there will be a good kernel?

[Joseph Salisbury (jsalisbury)]

We are bisecting between those two kernel versions to identify the commit that introduced this regression. Some of the test kernels I post will be bad and some will be good. At the end of the testing the bisect will point to one particular commit.

I built the first test kernel, up to the following commit:
aee3bfa3307cd0da2126bdc0ea359dabea5ee8f7

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1657994

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[Ian Bruce (ian-bruce)]

I would like to add some information to this bug report, which may or may not be relevant.
There seems to be a general problem with HDMI audio in recent kernel versions.
I am using Debian kernel packages, on an AMD64 system with a Radeon R9-280 video card:

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti PRO [Radeon HD 7950/8950 OEM / R9 280]
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti HDMI Audio [Radeon HD 7870 XT / 7950/7970]

My experience has been as follows:

Linux v4.6.4 -- HDMI audio works

Linux v4.9.2 -- HDMI audio works

Linux v4.9.6 -- HDMI audio does not work

There were also problems with kernel versions 4.7 and 4.8. I had the impression that
it was intermittent; sometimes when the audio did not work, a reboot or power cycle
into the same kernel version would make it start working. It appears that with my
hardware, Linux v4.6 was completely reliable; more recent versions are substantially
less so, or even completely broken. (I'm not exactly sure whether v4.9.2 always worked,
or only most of the time.)

I hope this information is useful in locating the specific source of the problem.

<email address hidden>

[Joseph Nuzman (jnuzman)]

I had been trying to cherry-pick patches from the working Xenial kernel to mainline, and got bogged down with build issues. Back to the bisection:

This kernel ...
http://kernel.ubuntu.com/~jsalisbury/lp1657994/linux-image-4.4.0-040400-generic_4.4.0-040400.201702021530_amd64.deb
.. does not work. Failure mode like 4.4 mainline.

I can also update that mainline kernels 4.10.3 and 4.11-rc2 both fail like other recent mainline kernels.

To recap, we have only two working data points, both Xenial kernels (4.4+i915 backport).
4.4.0-59
4.4.0-21

All mainline 4.4 kernels do not even enumerate HDMI audio.

All mainline kernels from 4.5-rc1 and later enumerate HDMI audio but produce no sound.

[Kai-Heng Feng (kaihengfeng)]

Do you have any alsa/pulseaudio config?

This can be quickly verified by running "vanilla" Ubuntu.

16.04: http://cdimage.ubuntu.com/xenial/daily-live/current/
17.04: http://cdimage.ubuntu.com/daily-live/current/

If both of them work, then it's probably related to your config setting.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu Yakkety) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Joseph Nuzman (jnuzman)]

The bug has been fixed with this commit upstream drm-tip repository (with cc to stable):
https://cgit.freedesktop.org/drm-tip/commit/?id=d81fb7fd9436e81fda67e5bc8ed0713aa28d3db2

Note it also affects Zesty.