individual characters frequently corrupted

[Nick Moffitt]

Since upgrading to saucy, I've had individual characters render improperly. Unfortunately, taking a screenshot clears the corruption. Selecting the text, scrolling in the terminal (which I imagine redraws anew instead of scrolling a rendered pane), or any number of things that would trigger a re-display of a glyph seems to clear it. Incidentally I see occasional corrupted glyphs appear in this text input box as I type, and they will appear with one keystroke and disappear with the next. I am fairly confident I could reproduce as I go.

I filed this against pango because that's what I think of as responsible for this sort of thing.

Screenshot attached.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: libpangox-1.0-0 0.0.2-4
ProcVersionSignature: Ubuntu 3.11.0-7.14-generic 3.11.1
Uname: Linux 3.11.0-7-generic x86_64
ApportVersion: 2.12.2-0ubuntu1
Architecture: amd64
Date: Thu Sep 19 11:24:26 2013
EcryptfsInUse: Yes
MarkForUpload: True
SourcePackage: pangox-compat
UpgradeStatus: Upgraded to saucy on 2013-09-17 (1 days ago)

[Dennis (daustmann-j-deactivatedaccount-deactivatedaccount)]

Same here on a Lenovo T400 with Intel Graphics. Also got a compiz crash after my first login on a fresh installation.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Lonnie Lee Best (launchpad-startport)]

I'm experiencing this too after upgrading to Ubuntu 13.10. I was delighted to find this bug report, because I didn't want to have to explain the whole think myself.

I was reading an article in Firefox when I noticed it. I had the article scaled up a knotch, and while scrolling text it would flicker a little as though it was having to re-render a paragraph 5 words at a time (while scrolling). This was happening super quick, but the flickering pattern (I was able to perceive) seemed like I'm describing.

As you said, it doesn't happen every time you scroll, but sometimes (after scrolling) you'll stop (oh my, it just did it while I was typing: the "p" in the word "stop" became corrupted) and one or two letters on the entire page become graphically corrupted where you can't make them out (in and of themselves).

Like you say, as soon as you hit the "Print Scrn" button the corruption goes away before you can capture a screen shot of it. Also, if you click the page containing the corrupted letter, the corrupted letter goes away. I don't have a camera handy, but it seems the only way to show it exactly what we are talking about is to take a picture of it with an outside device.

Actually, I've just done a video capture that shows the corruption. See attachment.

[Nick Moffitt (nick-moffitt)]

Lonnie Lee Best:
> Actually, I've just done a video capture that shows the corruption.
> ** Attachment added: "out.ogv"
> https://bugs.launchpad.net/ubuntu/+source/pangox-compat/+bug/1227569/+attachment/3883106/+files/out.ogv

Thank you so much for making this video! I wish I'd thought to do the
same thing.

Unfortunately this bug didn't get confirmation until after the final
freeze, so I worry it won't get much attention for a while. It's more
of an irritant than anything else (it doesn't affect the underlying
data, and most minor amounts of activity flush the effects), so I just
hope it doesn't persist into the next LTS!

--
Nick Moffitt

[Martin Olsson (mnemo)]

I have it as well, looks exactly like in Nick's video. My intel card is:
00:02.0 VGA compatible controller [0300]: Intel Corporation 4 Series Chipset Integrated Graphics Controller [8086:2e22] (rev 03)

[Lonnie Lee Best (launchpad-startport)]

My video card too is intel 4 series:

 lspci :

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Lonnie Lee Best (launchpad-startport)]

Perhaps we have not submitted this bug to the right package yet?

Is this bug limited to users having the Intel Series 4 graphics cards? If so, maybe there was a flawed update to the kernel dealing with the graphics drivers of this series of intel graphics cards.

@Nick Moffitt: Can you post the output of this command:
lspci | grep 'VGA\|Display'

[Lonnie Lee Best (launchpad-startport)]

In the meantime, maybe the kernel developers can provide us some direction:
https://bugzilla.kernel.org/show_bug.cgi?id=63891

[Nick Moffitt (nick-moffitt)]

Lonnie Lee Best:
> @Nick Moffitt: Can you post the output of this command:
> lspci | grep 'VGA\|Display'

    00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
    00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

--
Nick Moffitt

[Matteo Dell'Amico (della)]

Same problem for me:

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Dave Wickham (dave.wickham)]

Just adding a "me too":

00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 07)
00:02.1 Display controller [0380]: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a43] (rev 07)

Apparently this is using the i915 kernel driver and the intel Xorg driver, and most of the places that refer to it (dmesg, Xorg log, etc) refer to it as a GM45:

[ 50.345] (--) intel(0): Integrated Graphics Chipset: Intel(R) GM45

I assume this is the same with everyone else.

[Lonnie Lee Best (launchpad-startport)]

I'm super busy today; do any of you have time to test an older kernel with Ubuntu 13.10 so we can be sure that it is indeed the Kernel update that is causing our issue in 13.10?

Daniel Vetter 2013-10-27 21:57:03 UTC says:

Are you sure this is the kernel, i.e. have you installed an older one and the corruptions are gone?

Please also test whether switching to UXA in the ddx works around the issue.

Reply here please: https://bugzilla.kernel.org/show_bug.cgi?id=63891

[alaink (toccata69)]

I'm experiencing the same bug minutes after upgrading from 3.8 to 3.11

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Dominik Wiernicki (dmnk-89)]

same problem

$ lspci | grep 'VGA\|Display'
00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)

[Becir (blabla-2)]

I experience the same problem as all of you

$ lspci | grep 'VGA\|Display'
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Lonnie Lee Best (launchpad-startport)]

 Gabor MICSKO 2013-11-03 10:58:18 UTC

(In reply to Gabor MICSKO from comment #5)
> I will test it with older kernels soon.

Same problem with an older kernel.

# cat /etc/issue
Ubuntu 13.10 \n \l

# uname -a
Linux foobar 3.8.0-31-generic #46-Ubuntu SMP Tue Sep 10 19:56:49 UTC 2013 i686 i686 i686 GNU/Linux

# lspci | grep 'VGA\|Display'
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

Char corruption problem also exist with this kernel. UXA or SNA it makes no difference.

Source: https://bugzilla.kernel.org/show_bug.cgi?id=63891

[Lonnie Lee Best (launchpad-startport)]

Now that someone has tested Ubuntu 13.10 with the same kernel that was used in Ubuntu 13.04, and he confirmed that this bug persists in both UXA and SNA modes (in 13.10), it appears (so far) that it is not the new kernel's fault.

So, given that this bug didn't exist in Ubuntu 13.04 and now exist with multiple kernels in 13.10, have we yet reported this to the correct package-project?

If we can get this bug in front of the right person, the fix will likely be quick and easy.

[meWho (mewho)]

I experience the same problem:

# lspci | grep 'VGA\|Display'
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Bit32 (bit32)]

Another user with the same problem here.

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Johann Bach (johann-bach-deactivatedaccount)]

I am experiencing the character corruption issue, but I am not using Intel graphics; I'm using AMD/ATI Radeon HD 7950 graphics with the recommended driver.

lspci | grep VGA
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti PRO [Radeon HD 7950]

[tubby (tromp-wezelman)]

Same issue. I have the following:
00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

[Lonnie Lee Best (launchpad-startport)]

This might not seem like a crucial bug, but it's really starting to get on my nerves.

Is there anything else we can do to get this issue routed to correct developer (who can fix it)?

[panaak (panaak)]

same problem here:

$ uname -a
Linux mubu 3.11.0-14-generic #21-Ubuntu SMP Tue Nov 12 17:07:40 UTC 2013 i686 i686 i686 GNU/Linux
$ lspci |grep Graph
00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)

only it seems that the corruption only happens while rendering fonts in terminal.. chrome and other places is ok i think..

[JeromeV (jeromev)]

Same problem here.
Looks like no one cares.

[jayhawk (jayhawk)]

I too had this problem on my Lenovo SL510 with Ubuntu 13.10.
However this solved the problem for me:

In Synaptic I found 4 ibus related packages with status 'installed, but upgradable'. I upgraded these, and now the corrupted chars problem seems to be gone.

[jayhawk (jayhawk)]

RE: #26
Sorry, false alarm. I still got the problem!

[Becir (blabla-2)]

Hi!
I have found the following bug report which seems to me to be very much related:
https://bugs.freedesktop.org/show_bug.cgi?id=55500
Especially the latest comments look very promising (see comment #129). It looks like there might be a working patch.

I really hope there is someone here who is more experienced linux user than me. Because I am not able to apply/test the patch to confirm if my assumption is correct at all.

I look forward to receiving your reply.

[Antonio (tritemio)]

Hi, same proble here. lscpi -v:

00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) (rev 0c) (prog-if 00 [VGA controller])
 Subsystem: Dell Device 026f
 Flags: bus master, fast devsel, latency 0, IRQ 47
 Memory at f8000000 (64-bit, non-prefetchable) [size=1M]
 Memory at d0000000 (64-bit, prefetchable) [size=256M]
 I/O ports at 1800 [size=8]
 Expansion ROM at <unassigned> [disabled]
 Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
 Capabilities: [d0] Power Management version 3
 Kernel driver in use: i915

Another screenshot or the problem can be found here:
http://askubuntu.com/questions/373520/after-the-upgrade-13-04-to-13-10-i-have-problems-with-characters-rendering-in-a

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[penalvch (penalvch)]

Nick Moffitt, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p xserver-xorg-video-intel REPLACE-WITH-BUG-NUMBER

Please note, given that the information from the prior release is already available, doing this on a release prior to the development one would not be helpful.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Lonnie Lee Best (launchpad-startport)]

.tmp.unity.support.test.0:

ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
DistUpgraded: 2013-10-17 22:50:17,912 DEBUG enabling apt cron job
DistroCodename: saucy
DistroRelease: Ubuntu 13.10
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:02a0]
   Subsystem: Dell Device [1028:02a0]
InstallationDate: Installed on 2013-10-07 (93 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Dell Inc. Studio 1737
MarkForUpload: True
NonfreeKernelModules: wl
Package: xserver-xorg-video-intel 2:2.99.904-0ubuntu2
PackageArchitecture: amd64
ProcEnviron:
 LANGUAGE=en_US
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-15-generic root=UUID=7c3ef483-50e8-4685-9adb-038e70e36e45 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.11.0-15.23-generic 3.11.10
Tags: saucy ubuntu compiz-0.9
Uname: Linux 3.11.0-15-generic x86_64
UpgradeStatus: Upgraded to saucy on 2013-10-18 (82 days ago)
UserGroups:

dmi.bios.date: 04/14/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A09
dmi.board.name: 0P792H
dmi.board.vendor: Dell Inc.
dmi.board.version: A09
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: A09
dmi.modalias: dmi:bvnDellInc.:bvrA09:bd04/14/2011:svnDellInc.:pnStudio1737:pvrA09:rvnDellInc.:rn0P792H:rvrA09:cvnDellInc.:ct8:cvrA09:
dmi.product.name: Studio 1737
dmi.product.version: A09
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.10+13.10.20131011-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.46-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.2.1-1ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.2.1-1ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.14.3-3ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu3.1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.2.0-0ubuntu10
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.904-0ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.9-2ubuntu1
xserver.bootTime: Wed Jan 8 08:32:48 2014
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 0
 vendor LPL
xserver.version: 2:1.14.3-3ubuntu2

[Lonnie Lee Best (launchpad-startport)]

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[Lonnie Lee Best (launchpad-startport)]

I'm still experiencing this issue.

[penalvch (penalvch)]

Lonnie Lee Best, please do not apport-collect to another person's report. Instead, if you have a bug in Ubuntu, please feel free to file a new report by executing the following in a terminal:
ubuntu-bug xorg

For more on this, please see the official Ubuntu documentation:
Ubuntu X.Org Team, Ubuntu Bug Control, and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report will delay your problem being addressed as quickly as possible.

Thank you for your understanding.

[Lonnie Lee Best (launchpad-startport)]

If I created a new bug report, it would be a duplicate of this one; this report is my exact problem, and it remains unfixed on my fully updated Ubuntu 13.10.

[Jmadero (jmadero)]

What can I do to get this bug out of invalid state. If you google "font corruption ubuntu 13.10" quite a few people are reporting it. It's pretty nasty as it affects every piece of software and makes font rendering unreadable. It must be an intel issue and if that's the case it'd be best to go to an older driver (13.04)

[penalvch (penalvch)]

Jmadero, this bug is not in an Invalid state. One may notice at the top of this report it notes:
This bug report is a duplicate of: Bug #1098334: [gen4 sna] Font corruption.

As well, stating how many people may have reported something, is not terribly helpful. However, what would be is if you have hardware that demonstrates this problem, please feel free to file a new report by executing the following in a terminal:
ubuntu-bug xorg

Please ensure you have xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

For more on this, please see the official Ubuntu documentation:
Ubuntu X.Org Team, Ubuntu Bug Control, and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Please note, not filing a new report will delay your problem being addressed as quickly as possible.

Thank you for your understanding.

[RickB (rick-777)]

This bug has affected me since upgrading to Trusty. My machine has been far less stable since the upgrade. Graphics/display crashes seem to be behind the problem.

$ lspci | grep 'VGA\|Display'
01:00.0 VGA compatible controller: NVIDIA Corporation G92 [GeForce GTS 250] (rev a2)

[David Pérez (david-perez-ingeniero)]

I'm experiencing also this nasty bug:

$ lspci|grep -i graphic
00:02.0 VGA compatible controller: Intel Corporation 82Q963/Q965 Integrated Graphics Controller (rev 02)
00:02.1 Display controller: Intel Corporation 82Q963/Q965 Integrated Graphics Controller (rev 02)

[kostas groutsis (kgroutsis)]

I'm also experiencing this bug on a Dell Latitude E7450 with 14.04 and latest kernel 3.16.0-37

$ lspci|grep -i graphic
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09)

[penalvch (penalvch)]

kostas groutsis, given you have a different chipset, it will help immensely if you filed a new report via a terminal:

ubuntu-bug xorg

Please ensure you have xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

Also, please feel free to subscribe me to it.

[Alberto Mardegan (mardy)]

Hi Christopher, I filed bug 1470392, for my radeon card.

[David Pérez (sanete)]

Current workarounds:
- Reboot the system.
- With Firefox, increasing font size with Ctrl + plus, has shown again the text correctly.

Possible solutions for me:
- Use Windows
- Buy a new computer
- Try some help for the community.
- Try to use an old driver.