Video acceleration regression for Radeon Xpress 200M (r300) in xorg-lts-xenial & xorg-lts-wily

[indigocat]

After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and xserver-xorg-video-radeon-lts-xenial), system boots up fine and responsively, but screen is laggy; there is a tremendous performance regression in comparison to xorg-lts-vivid. Lots of video tearing that did not occur when using xserver-xorg-video-radeon-lts-vivid.

System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon Xpress 200M chip (r300 driver). Video acceleration was working with DRI2 under the Vivid stack (kernel 3.19-64-lowlatency + xserver-xorg-video-radeon-lts-vivid).
I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video acceleration works fine with the Vivid xorg.

I reported this in launchpad previously, and it was dismissed as "invalid" since Wily is EOL.
The problem, however, persists in the Xenial stack, so I'm reporting it here.

Attached are the respective Xorg.0 logs.

[indigocat (indigocat)]

I've just upgraded the kernel to 4.4.0-34-lowlatency by installing the linux-image-lowlatency-lts-xenial package.
Video acceleration works just fine combined with the xserver-xorg-video-radeon-lts-vivid (DRI2).

Problems begin when using xserver-xorg-video-radeon-lts-wily or xserver-xorg-video-radeon-lts-xenial.

Tearing ensues, regardless of the presence of a xorg.conf config file to enable/disable options to improve framerate. Enabling DRI3 only worsens the performance regression, and accentuates tearing.

[Timo Aaltonen (tjaalton)]

does stock 16.04 work better?

[indigocat (indigocat)]

I tried stock 16.04, and upstream xorg; no improvement.

What I've identified is: any xorg version that supports DRI3 shows a performance regression even if only DRI2 is active. Enabling DRI3 worsens video performance and tearing.

xorg-lts-vivid is the latest version that will work flawlessly.

[indigocat (indigocat)]

Any ideas?

[indigocat (indigocat)]

Ok, since you don't seem to believe this, here are 2 videos: the first is using the Vivid xorg stack, YouTube fullscreen on Chromium. The second video is the same, under the Xenial stack.

Vivid: https://youtu.be/Ykhp2L_pf7Y
Xenial: https://youtu.be/p7FvXTzlIa0

The regression is patent, and it was already there in Wily, so EOL isn't really a reason.

[indigocat (indigocat)]

The reason I'm reporting this problem is:
I'm running Ubuntu 14.04, I have no plans to upgrade to 16.04 (older laptop, maxed out at 2Gb RAM), yet System Update insists on suggesting to upgrade my HWE stack (Vivid: EOL). Doing so results in a show-stopping video performance degradation.

[Timo Aaltonen (tjaalton)]

first bisect between 7.5.0..git20150819 at

http://koti.kapsi.fi/~tjaalton/lp1610591

[indigocat (indigocat)]

I'll have to ask someone else to do help me out with this, as this machine has no more disk space to store repos, not enough power to compile quickly, and not enough time off-production to do both.

I'll get back here as soon as I can.

[Timo Aaltonen (tjaalton)]

huh? you don't have disk space to install the package? I did the bisect for you...

and there's absolutely no point in filing a bug on Debian asking if someone else is seeing this

[indigocat (indigocat)]

Sorry man, I was just looking for extra help.

Yes, I don't have enough space, there's less than 1 Gb free (about which
the system constantly warns), I have no external drive to dd my home
partition (I've been awfully broke for 2 years), and I can't delete stuff
yet until I'm done with some projects on this machine (rendering &
plotting).

I'm pretty much screwed in terms of testing infrastructure now; a couple of
years ago, I could have built kernels daily.

Again, sorry for the inconvenience.

El mié., 31 de agosto de 2016 17:06, Timo Aaltonen <email address hidden>
escribió:

> huh? you don't have disk space to install the package? I did the bisect
> for you...
>
> and there's absolutely no point in filing a bug on Debian asking if
> someone else is seeing this
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1610591
>
> Title:
> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
> lts-xenial & xorg-lts-wily
>
> Status in xserver-xorg-driver-ati:
> Unknown
> Status in xserver-xorg-video-ati package in Ubuntu:
> Incomplete
>
> Bug description:
> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
> responsively, but screen is laggy; there is a tremendous performance
> regression in comparison to xorg-lts-vivid. Lots of video tearing that
> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>
> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
> under the Vivid stack (kernel 3.19-64-lowlatency +
> xserver-xorg-video-radeon-lts-vivid).
> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
> acceleration works fine with the Vivid xorg.
>
> I reported this in launchpad previously, and it was dismissed as
> "invalid" since Wily is EOL.
> The problem, however, persists in the Xenial stack, so I'm reporting it
> here.
>
> Attached are the respective Xorg.0 logs.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/1610591/+subscriptions
>
--
dennis mayr
|mobile > +56 [9] 5867 8727

[Timo Aaltonen (tjaalton)]

Look, all you need to do is install the package (which replaces xserver-xorg-video-ati-lts-xenial you already have installed, so no extra space taken) and report back if it works or not. Then you get another build to test and eventually there is a commit identified to tell upstream about...

[Timo Aaltonen (tjaalton)]

hang on, that's the wrong package :D I need to copy -radeon there..

[indigocat (indigocat)]

Will do, I'll keep you posted either in 3 more hours, or tomorrow early in
the morning.
Cheers!

El mié., 31 de agosto de 2016 18:00, Timo Aaltonen <email address hidden>
escribió:

> hang on, that's the wrong package :D I need to copy -radeon there..
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1610591
>
> Title:
> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
> lts-xenial & xorg-lts-wily
>
> Status in xserver-xorg-driver-ati:
> Unknown
> Status in xserver-xorg-video-ati package in Ubuntu:
> Incomplete
>
> Bug description:
> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
> responsively, but screen is laggy; there is a tremendous performance
> regression in comparison to xorg-lts-vivid. Lots of video tearing that
> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>
> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
> under the Vivid stack (kernel 3.19-64-lowlatency +
> xserver-xorg-video-radeon-lts-vivid).
> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
> acceleration works fine with the Vivid xorg.
>
> I reported this in launchpad previously, and it was dismissed as
> "invalid" since Wily is EOL.
> The problem, however, persists in the Xenial stack, so I'm reporting it
> here.
>
> Attached are the respective Xorg.0 logs.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/1610591/+subscriptions
>
--
dennis mayr
|mobile > +56 [9] 5867 8727

[indigocat (indigocat)]

(I forgot a small detail: this machine can only run on 32bits)

dennis*mayr*
*|**mobile **>* *+56 [9] 5867 8727*

On 31 August 2016 at 19:02, Dennis Mayr <email address hidden> wrote:

> Will do, I'll keep you posted either in 3 more hours, or tomorrow early in
> the morning.
> Cheers!
>
> El mié., 31 de agosto de 2016 18:00, Timo Aaltonen <email address hidden>
> escribió:
>
>> hang on, that's the wrong package :D I need to copy -radeon there..
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1610591
>>
>> Title:
>> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
>> lts-xenial & xorg-lts-wily
>>
>> Status in xserver-xorg-driver-ati:
>> Unknown
>> Status in xserver-xorg-video-ati package in Ubuntu:
>> Incomplete
>>
>> Bug description:
>> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
>> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
>> responsively, but screen is laggy; there is a tremendous performance
>> regression in comparison to xorg-lts-vivid. Lots of video tearing that
>> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>>
>> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
>> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
>> under the Vivid stack (kernel 3.19-64-lowlatency +
>> xserver-xorg-video-radeon-lts-vivid).
>> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
>> acceleration works fine with the Vivid xorg.
>>
>> I reported this in launchpad previously, and it was dismissed as
>> "invalid" since Wily is EOL.
>> The problem, however, persists in the Xenial stack, so I'm reporting it
>> here.
>>
>> Attached are the respective Xorg.0 logs.
>>
>> To manage notifications about this bug go to:
>> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/
>> 1610591/+subscriptions
>>
> --
> dennis mayr
> |mobile > +56 [9] 5867 8727
>

[Timo Aaltonen (tjaalton)]

alright, uploaded to ppa:tjaalton/test

https://launchpad.net/~tjaalton/+archive/ubuntu/test

[indigocat (indigocat)]

Excellent, downloading right now...

El jue., 1 de septiembre de 2016 8:46, Timo Aaltonen <email address hidden>
escribió:

> alright, uploaded to ppa:tjaalton/test
>
> https://launchpad.net/~tjaalton/+archive/ubuntu/test
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1610591
>
> Title:
> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
> lts-xenial & xorg-lts-wily
>
> Status in xserver-xorg-driver-ati:
> Unknown
> Status in xserver-xorg-video-ati package in Ubuntu:
> Incomplete
>
> Bug description:
> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
> responsively, but screen is laggy; there is a tremendous performance
> regression in comparison to xorg-lts-vivid. Lots of video tearing that
> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>
> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
> under the Vivid stack (kernel 3.19-64-lowlatency +
> xserver-xorg-video-radeon-lts-vivid).
> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
> acceleration works fine with the Vivid xorg.
>
> I reported this in launchpad previously, and it was dismissed as
> "invalid" since Wily is EOL.
> The problem, however, persists in the Xenial stack, so I'm reporting it
> here.
>
> Attached are the respective Xorg.0 logs.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/1610591/+subscriptions
>
--
dennis mayr
|mobile > +56 [9] 5867 8727

[indigocat (indigocat)]

Just tested the drivers, video playback tear and GUI lag are still there.
We can cross 7.7.0-1 off the list.

dennis*mayr*
*|**mobile **>* *+56 [9] 5867 8727*

On 1 September 2016 at 09:46, Dennis Mayr <email address hidden> wrote:

> Excellent, downloading right now...
>
> El jue., 1 de septiembre de 2016 8:46, Timo Aaltonen <email address hidden>
> escribió:
>
>> alright, uploaded to ppa:tjaalton/test
>>
>> https://launchpad.net/~tjaalton/+archive/ubuntu/test
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1610591
>>
>> Title:
>> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
>> lts-xenial & xorg-lts-wily
>>
>> Status in xserver-xorg-driver-ati:
>> Unknown
>> Status in xserver-xorg-video-ati package in Ubuntu:
>> Incomplete
>>
>> Bug description:
>> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
>> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
>> responsively, but screen is laggy; there is a tremendous performance
>> regression in comparison to xorg-lts-vivid. Lots of video tearing that
>> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>>
>> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
>> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
>> under the Vivid stack (kernel 3.19-64-lowlatency +
>> xserver-xorg-video-radeon-lts-vivid).
>> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
>> acceleration works fine with the Vivid xorg.
>>
>> I reported this in launchpad previously, and it was dismissed as
>> "invalid" since Wily is EOL.
>> The problem, however, persists in the Xenial stack, so I'm reporting it
>> here.
>>
>> Attached are the respective Xorg.0 logs.
>>
>> To manage notifications about this bug go to:
>> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/
>> 1610591/+subscriptions
>>
> --
> dennis mayr
> |mobile > +56 [9] 5867 8727
>

[Timo Aaltonen (tjaalton)]

ok, ~trusty2.2 uploaded

[indigocat (indigocat)]

Tested; fullscreen YouTube playback *somewhat* improved by a notch, but it
takes about 5 seconds to begin playing smoothly at 360p.
When going back to windowed/embedded playback, framerate plummets. Same
with other video sources.
Xorg 7.5.0-1 still stands out undefeated.

El vie., 2 sept. 2016 a las 6:06, Timo Aaltonen (<email address hidden>)
escribió:

> ok, ~trusty2.2 uploaded
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1610591
>
> Title:
> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
> lts-xenial & xorg-lts-wily
>
> Status in xserver-xorg-driver-ati:
> Unknown
> Status in xserver-xorg-video-ati package in Ubuntu:
> Incomplete
>
> Bug description:
> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
> responsively, but screen is laggy; there is a tremendous performance
> regression in comparison to xorg-lts-vivid. Lots of video tearing that
> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>
> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
> under the Vivid stack (kernel 3.19-64-lowlatency +
> xserver-xorg-video-radeon-lts-vivid).
> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
> acceleration works fine with the Vivid xorg.
>
> I reported this in launchpad previously, and it was dismissed as
> "invalid" since Wily is EOL.
> The problem, however, persists in the Xenial stack, so I'm reporting it
> here.
>
> Attached are the respective Xorg.0 logs.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/1610591/+subscriptions
>
--
dennis mayr
|mobile > +56 [9] 5867 8727

[penalvch (penalvch)]

Timo Aaltonen, any news on the next step of the bisect?

[indigocat (indigocat)]

BTW, I just finished testing the following scenarios, just to rule out a kernel-related issue:
-Xserver: 1.18
-xserver-xorg-video-ati: 7.7

On kernels:
-3.13.0-95
-3.16.0-77
-3.19.0-68
-4.2.0-42
-4.4.0-36

Video lags on all kernels.

When using:
-Xserver: 1.16
-xserver-xorg-video-ati: 7.5

on the above kernels, video and GUI respond smoothly.

[Timo Aaltonen (tjaalton)]

new version available that now builds too

[indigocat (indigocat)]

Excellent, I'll test it this afternoon!

El lun., 5 de septiembre de 2016 11:11, Timo Aaltonen <email address hidden>
escribió:

> new version available that now builds too
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1610591
>
> Title:
> Video acceleration regression for Radeon Xpress 200M (r300) in xorg-
> lts-xenial & xorg-lts-wily
>
> Status in xserver-xorg-driver-ati:
> Unknown
> Status in xserver-xorg-video-ati package in Ubuntu:
> New
>
> Bug description:
> After updating the Ubuntu HWE stack in 14.04 to Xenial (kernel 4.4 and
> xserver-xorg-video-radeon-lts-xenial), system boots up fine and
> responsively, but screen is laggy; there is a tremendous performance
> regression in comparison to xorg-lts-vivid. Lots of video tearing that
> did not occur when using xserver-xorg-video-radeon-lts-vivid.
>
> System is an older Pentium laptop (Packard Bell EasyNote) with a Radeon
> Xpress 200M chip (r300 driver). Video acceleration was working with DRI2
> under the Vivid stack (kernel 3.19-64-lowlatency +
> xserver-xorg-video-radeon-lts-vivid).
> I also tried upgrading to the Wily kernel (4.2.0-lowlatency), and video
> acceleration works fine with the Vivid xorg.
>
> I reported this in launchpad previously, and it was dismissed as
> "invalid" since Wily is EOL.
> The problem, however, persists in the Xenial stack, so I'm reporting it
> here.
>
> Attached are the respective Xorg.0 logs.
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/1610591/+subscriptions
>
--
dennis mayr
|mobile > +56 [9] 5867 8727

[indigocat (indigocat)]

System GUI (GTK) doesn't seem laggy, but web video playback still shows a lot of tearing (Chromium, windowed or fullscreen).

Something odd happened in Chromium web video playback: it doesn't go fullscreen properly when using this driver (looks like windowed-mode fullscreen).
When reverting to the 7.5 driver, video playback in Chromium does proper, actual fullscreen with constant, fluid framerate.

[indigocat (indigocat)]

BTW, tearing/low framerate also occurs in VLC and Kodi, which normally have fluid playback due to low overhead.

[Timo Aaltonen (tjaalton)]

ok, new version uploaded, should be available soon

[indigocat (indigocat)]

Tested; Chromium allows proper fullscreen again, gtk system GUI is still responsive, but video tearing isn't going away; for a couple of seconds it recedes slightly, but then comes back, both in windowed mode and fullscreen.

As for VLC and Kodi, there's no really noticeable tearing now, but the framerate drops intermittently every 3 seconds, in average, like a hiccup.

We could say there's a bit of an improvement with this build.

[Timo Aaltonen (tjaalton)]

ok, 2.4 uploaded

for reference the bisect git sha's are:
~trusty2.1 5921ba4ca705a0d919515626088f3948cc4848c1
~trusty2.2.1 3c65fb849e1ba9fb6454bcaa55b696548902f3fc
~trusty2.3 b8ec9ed4fe86952763b963c86f0af0dcae69aa6c
~trusty2.4 c88424d1f4aaa78b569e5d44f0b4a47de2f422f4

[indigocat (indigocat)]

2.4 tested; window-embedded Youtube on Chromium tears during the first 3 seconds, then plays back a bit smoother than 2.3 (less frequent hiccups).
Regarding fullscreen Chromium and VLC/Kodi,no changes observed.

[Timo Aaltonen (tjaalton)]

btw, are you using, or trying to use vdpau? I believe your bug is caused by:

commit 7c7b38e0b375b6e8853ad2d1092302ea83f6f570
Author: David Heidelberger <email address hidden>
Date: Sun Oct 12 16:34:21 2014 +0200

    radeon/vdpau: don't report VDPAU for < r300

so after this commit RS200 won't get vdpau

[Timo Aaltonen (tjaalton)]

hmm no, the logfile from 7.7 shows vdpau is enabled..

[indigocat (indigocat)]

Indeed, I am using VDPAU since 7.5, as it has shown to improve video playback framerates on computers like mine.
If needed, I can try 7.7 without VDPAU and see what happens...?

[penalvch (penalvch)]

indigocat, the next step is to fully commit bisect from xserver-xorg-video-ati 7.5 to 7.7 in order to identify the last good commit, followed immediately by the first bad one. This will allow for a more expedited analysis of the root cause of your issue. Could you please do this following https://wiki.ubuntu.com/X/Bisecting ?

Please note, finding adjacent versions is not fully commit bisecting.

It is most helpful that after the fix commit (not version) has been identified, you then mark this report Status New.

Thank you for your help.

[indigocat (indigocat)]

FTR, last working version is 7.5.0-1. Regression is first observed in version 7.5.0+git20150819.
At the moment it's hard for me to bisect (older production machine, not enough disk space to install dev-essentials, can't free up space until at least next week).
I'll have to try later.

[Timo Aaltonen (tjaalton)]

~trusty2.5 uploaded, this should work or there's something else going on, since there's only three commits left and none of those should have anything to do with this.

penalvch: I'm doing the bisection for dennis..

[indigocat (indigocat)]

Tested ~trusty2.5, no changes observed compared to ~trusty2.4. Tearing in fullscreen web videos (YouTube, Vimeo) persists, windowed mode runs a tad better, local video playback in VLC and Kodi improved (no tearing/hiccups, but a periodic lag that can be compared to time-shifting about every 4 seconds), but doesn't run as smoothly as the 7.5.0-1 radeon driver yet.

[Timo Aaltonen (tjaalton)]

~trusty2.6 uploaded, final version

[indigocat (indigocat)]

Tested ~trusty2.6.
Video playback in VLC and Kodi improved, couldn't notice hiccups not slowdowns this time.
Web video playback in Chromium still affected by tearing.

[Timo Aaltonen (tjaalton)]

well, 2.6 _is_ 7.5.0...

so you just proved that it's not the -ati driver causing it. The diff to 2.5 was:

c74de9fec13fac2 PRIME: Don't advertise offload capabilities when acceleration is disabled
636a6382f80412a Remove duplicate OPTION_PAGE_FLIP entry
c854b4479ec5122 radeon: bump version post release

none of which have anything to do with your usecase, so if you saw a difference in behaviour then that's funny, but not caused by the driver.

That leaves the kernel and mesa to bisect then, and at this point I'll give up.

[penalvch (penalvch)]

indigocat, to clarify, if you boot into a Vivid stack kernel (3.19.x) does this issue go away?

[indigocat (indigocat)]

Funny thing is, Ubuntu's stock 7.5.0-1 version gives me no tearing at all, whereas ~trusty2.6 does.

I'll test ~trusty2.6 with the Vivid kernel this afternoon.

[indigocat (indigocat)]

Done: booted with Vivid kernel (3.19.0-68).

Radeon driver version 7.7 (current lts-xenial) and Timo's bisected ~trusty2.6 show tearing in web videos in Chromium (the most efficient browser for this purpose).

[penalvch (penalvch)]

Timo Aaltonen, what bisection point would you like to see next?

[Timo Aaltonen (tjaalton)]

indigocat: how exactly are you able to install 7.5.0 so that it works with the lts-xenial stack?

[indigocat (indigocat)]

I updated the Xorg stack and drivers as recommended here: https://wiki.ubuntu.com/Kernel/LTSEnablementStack

sudo apt-get install --install-recommends xserver-xorg-core-lts-xenial xserver-xorg-lts-xenial xserver-xorg-video-all-lts-xenial xserver-xorg-input-all-lts-xenial libwayland-egl1-mesa-lts-xenial

Then I updated the packages uploaded to the PPA.
Then I tried them booting with different kernels.

[indigocat (indigocat)]

Just taking a wild guess (not my field): could this hypothetically be remotely related to DRI?

[Timo Aaltonen (tjaalton)]

if by dri you mean mesa, then yes

[indigocat (indigocat)]

Oh boy, this is getting more complex.
Perhaps I'll just stick with the Vivid Xorg stack for good, don't want this to become a waste of time.

[Timo Aaltonen (tjaalton)]

try 16.10

[indigocat (indigocat)]

Not using 14.04 anymore.

This can be closed if not affecting anybody else.

[penalvch (penalvch)]

As per https://bugs.launchpad.net/ubuntu/+source/mesa/+bug/1610591/comments/53 .