Regression: S-video output does not work

[Jarno Suni]

Regression. S-video output can not be used. It works by 4.4.0-22-generic.
xrandr tells on 4.4.0-31-generic:

TV1 unknown connection (normal left inverted right x axis y axis)
   848x480 50.00 +
   640x480 50.00 +
   1024x768 50.00
   800x600 50.00

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-31-generic 4.4.0-31.50
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jarnos 1573 F.... pulseaudio
CurrentDesktop: XFCE
Date: Sun Jul 31 17:15:16 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2016-04-28 (94 days ago)
InstallationMedia: Xubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: LENOVO 89224MG
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-31-generic root=UUID=15cc1d62-fbc6-4ce3-bf32-e35c61a921cf ro
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-31-generic N/A
 linux-backports-modules-4.4.0-31-generic N/A
 linux-firmware 1.157
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/13/06
dmi.bios.vendor: LENOVO
dmi.bios.version: 63ET13WW
dmi.board.name: CAPELL VALLEY(NAPA) CRB
dmi.board.vendor: LENOVO
dmi.board.version: Not Applicable
dmi.chassis.type: 10
dmi.chassis.vendor: No Enclosure
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnLENOVO:bvr63ET13WW:bd09/13/06:svnLENOVO:pn89224MG:pvr3000C200:rvnLENOVO:rnCAPELLVALLEY(NAPA)CRB:rvrNotApplicable:cvnNoEnclosure:ct10:cvrN/A:
dmi.product.name: 89224MG
dmi.product.version: 3000 C200
dmi.sys.vendor: LENOVO

[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 stable kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.4 stable 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/v4.4.16

[Jarno Suni (jarnos)]

I tried with 4.4.17-040417-generic.
Booting jammed in some startup job of cryptswap, but S-video output worked during boot unlike with other kernel.

[Joseph Salisbury (jsalisbury)]

The proposed Xenial kernel is now based on 4.4.16 and available in the -proposed repository. Would it be possible for you to test this latest kernel and post back if it resolves this bug?
See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

Thank you in advance!

[Jarno Suni (jarnos)]

I installed linux-image-4.4.0-36-generic (4.4.0-36.55) and xserver-xorg-video-intel (2:2.99.917+git20160325-1ubuntu1.1) from Proposed.

It did not resolve this bug.

[Jarno Suni (jarnos)]

Also problem with this system http://askubuntu.com/q/814358/21005

[Joseph Salisbury (jsalisbury)]

So 4.4.0-22 has the bug, but 4.4.0-31 does have the bug? From your testing of upstream 4.4.17 in comment #4 this sounds like it is related to an Ubuntu specific SAUCE patch. This would be confirmed by your test results of the -proposed kernel.

We can perform a kernel bisect to identify the commit that introduced this regression. We first need to identify the last good Ubuntu kernel and the first bad one. If -22 is good, we probably want to test 4.4.0-29 next. It can be downloaded from:

https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/10184098

[Jarno Suni (jarnos)]

4.4.0-22 does not have the bug.

[Joseph Salisbury (jsalisbury)]

Can you test the 4.4.0-29 kernel as well? A link to that kernel is posted in comment #8.

Note, with that kernel you need to install both the linux-image and linux-image-extra .deb packages.

[Jarno Suni (jarnos)]

The bug occurs when booted 4.4.0-29-generic.

[Joseph Salisbury (jsalisbury)]

Thanks for testing. We should narrow it down a bit more. Can you next test 4.4.0-25? It's available from:

https://launchpad.net/ubuntu/+source/linux/4.4.0-10.25/+build/9287900

[Jarno Suni (jarnos)]

I can not find 4.4.0-25 there, but 4.4.0-10.

[Jarno Suni (jarnos)]

With 4.4.0-10 it works as it used to.

[Joseph Salisbury (jsalisbury)]

Sorry, this is the correct link:

https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/9900269

[Jarno Suni (jarnos)]

The bug occurs with 4.4.0-25.

[Joseph Salisbury (jsalisbury)]

Thanks. So we now know 4.4.0-22 is good and 4.4.0-25 is bad. Can you next try 4.4.0-23 and 4.4.0-24:

4.4.0-23: https://launchpad.net/ubuntu/+source/linux/4.4.0-8.23/+build/9059173
4.4.0-24: https://launchpad.net/ubuntu/+source/linux/4.4.0-9.24/+build/9279168

[Jarno Suni (jarnos)]

No, because the links you gave are for 4.4.0-8 and 4.4.0-9.

[Joseph Salisbury (jsalisbury)]

Sorry, here are the correct links:

4.4.0-23: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/9755583
4.4.0-24: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/9887713

[Jarno Suni (jarnos)]

4.4.0-23 is bad, too

[Joseph Salisbury (jsalisbury)]

I started a kernel bisect between 4.4.0-22 and 4.4.0-23. The kernel bisect will require testing of about 7-10 test kernels.

I built the first test kernel, up to the following commit:
986aed37359b5c7dc72e0cc7217cbd48fc8efe7a

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

That sounds like a brute force method to me. Is it possible to contact the developers who made changes to those kernels and ask if they have an idea?

[Joseph Salisbury (jsalisbury)]

There are 261 commits between 4.4.0-22 and 4.4.0-23. It's difficult to tell which change caused this regression just by looking at the git log. A bisect would narrow down the exact commit that introduced this bug, and tell us who the author is to contact.

[Jarno Suni (jarnos)]

Can you give me a link to the commit log?

[Jarno Suni (jarnos)]

Could this bug be presented in some mailing list that the kernels developers follow? I still think that a developer may recognize he/she has contributed to the relevant part of code and find the cause of the bug more easily.

[Jarno Suni (jarnos)]

For what it is worth, S-video works by v4.8-rc5

[Jarno Suni (jarnos)]

I tested the kernel in lp1608236. S-video works.

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
3bfd2ce586e9ed143c10263981a6ec7fa5b40890

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

It has the bug.

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
dcf9fa00268dd24d9ecaa4f84cc6d07de8bd86a7

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

It does not have the bug.

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
c708299477b8592ae6e019aeff18f3b5e833ccea

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

It does not have the bug.

[Jarno Suni (jarnos)]

Was it all?

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
3d26b8d8361a9cfa098fe8548f1836573925cc7d

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

That kernel has the bug.

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
09535375a6da2c09497ef650a5de415148dd3b3b

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

The bug does not exist in the kernel.

We have already spent over 2 months to find the right kernel :(

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
732ce11060c0c4f7c2fa2d286e1006173fbd0904

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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.

There is only one more kernel to test after this one.

[Jarno Suni (jarnos)]

The bug seems not to exits in that one. Note that I did not remove earlier test 4.4.0-23-generic kernel before installing this one.

[Joseph Salisbury (jsalisbury)]

I built the final test kernel for the bisect, up to the following commit:
386e0f97a585fa6a6d4aad767884a760ce3c0782

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

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

[Jarno Suni (jarnos)]

That has the bug.

[Joseph Salisbury (jsalisbury)]

The bisect reported the following as the first bad commit:

commit 386e0f97a585fa6a6d4aad767884a760ce3c0782
Author: Maarten Lankhorst <email address hidden>
Date: Mon May 9 18:16:48 2016 -0600

    drm/atomic: Remove drm_atomic_connectors_for_crtc.

This is also commit 14de6c44d14 in mainline.

I built a test kernel with this commit reverted. The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1608236

Can you test that kernel and report back if it has the bug or not?

[Jarno Suni (jarnos)]

It does not have the bug.

[Joseph Salisbury (jsalisbury)]

Thanks for all the testing, I will contact the patch author for feedback. Can you run one additional test? Can you test the latest mainline kernel to see if there is already a fix for the bug? The 4.9-rc2 kernel can be downloaded from:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9-rc2/

[Jarno Suni (jarnos)]

4.9-rc2 does not have the bug.

[Joseph Salisbury (jsalisbury)]

Thanks for testing. I'll review the commit logs and ping the patch author and see if he knows which commit now fixes this bug in mainline. We can then SRU that commit to Xenial.

[Jarno Suni (jarnos)]

I am looking forward to seeing the bug fixed in kernel updates for Xenial.

[Joseph Salisbury (jsalisbury)]

Can you test the upstream stable 4.4 kernel to see if the fix has landed there yet? It is available from:

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.34/

[Jarno Suni (jarnos)]

Yes, it has landed there. Will it land to Xenial soon?

[Joseph Salisbury (jsalisbury)]

Those updates should get applied during this stable release cycle. Here is the current schedule:

Current cycle: 25-Nov through 17-Dec
====================================================================
         25-Nov Last day for kernel commits for this cycle
28-Nov - 03-Dec Kernel prep week.
04-Dec - 16-Dec Bug verification & Regression testing..
         19-Dec Release to -updates.

The -proposed kernel now has up to the 4.4.35 updates.

Would it be possible for you to test this latest kernel and post back if it resolves this bug?
See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

[Jarno Suni (jarnos)]

I get the same kernel (4.4.0.51.54) via , xenial-updates, xenial-security and xenial-proposed now. The bug is not fixed.

[Joseph Salisbury (jsalisbury)]

The -proposed kernel should be kernel 4.4.0-52.73. Can you run sudo apt-get update again?

If you still don't get the kernel, it can be downloaded directly from:
https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/11278866

[Jarno Suni (jarnos)]

The kernel does not resolve the bug.

[Joseph Salisbury (jsalisbury)]

It looks like commit 14de6c44d is in the Ubuntu 4.4 based kernel(It was added to resolve bug 1542939). However, the commit was never applied to upstream 4.4. That would explain why the bug does not exist in upstream 4.4, but it does in 4.4 based Xenial.

Can you see if this bug also exists in the 4.8 based Yakkety kernel? If it does, we may just have to revert 14de6c44d in Xenial.

The Yakkety kernel is available from:
https://launchpad.net/~canonical-kernel-security-team/+archive/ubuntu/ppa/+build/11288461

If the bug does exist in Yakkety, we could also see if this bug still exists in current mainline:
 http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9-rc8

[Jarno Suni (jarnos)]

It works. But colors are gone. Also with 4.4.0-22-generic. Maybe my hardware is breaking. I also tried to install linux-generic-hwe-16.04-edge to get newer kernel, but apt failed to fetch the .debs.

[Jarno Suni (jarnos)]

Why incomplete?

[Joseph Salisbury (jsalisbury)]

Sorry the status was changed, wrong bug.

Just to confirm, this bug does not exists with the Yakkety? If that is the case, there is another commit there that fixes this bug, since yakkety does in fact contain commit 14de6c44d.

[Jarno Suni (jarnos)]

S-video works by 4.8 based Yakkety kernel.

[Joseph Salisbury (jsalisbury)]

Thanks for testing Yakkety. I reviewed the git logs between Xenail and Yakkety and there are many drm commits. It would be easiest to perform a Reverse bisect.

Commit 14de6c44d was added to Yakkety in Ubuntu-4.6.0-0.1. Can you test the following kernel:
https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/bootstrap/+build/10600030

For a reverse bisect, we need to find the last bad kernel and first good one.