I recently upgraded from Ubuntu 13.04 to Ubuntu 13.10, which now uses the 3.11.0-12-generic Kernel. I believe that this kernel update may have provided updates to my video card drivers that have lead to individual text-characters often being corrupted, because the issue spans all applications that display text. To see the issue I'm having, please view this bug report while giving careful attention to the video that is posted at the top of comment #4: https://bugs.launchpad.net/bugs/1227569 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)
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.
I'm not totally sure yet, but I've relayed your question to this thread: https://bugs.launchpad.net/bugs/1227569 However, I suspect it is kernel-related due to the fact that everyone reporting this issue seems to have roughly the same Intel 4 Series graphics card.
(In reply to Lonnie Lee Best from comment #2) > However, I suspect it is kernel-related due to the fact that everyone > reporting this issue seems to have roughly the same Intel 4 Series graphics > card. We have some lingering issues with small corruptions on gen4. If it's that one then a big flush hammer works around it (and using UXA essentially does that), but we haven't found something better yet. So if I'm right it's a ddx issue, not a kernel bug at all. Or do you have some direct evidence that points at the kernel and not the userspace parts of the driver being the culprit?
Speaking as someone else who had this issue with the same hardware/distro combination, switching to UXA appears to have eliminated the corruption. Interestingly, the previous Ubuntu release also used SNA and didn't have this corruption, so this appears to be new, but probably not a kernel issue from what you're saying.
(In reply to Dave Wickham from comment #4) > Speaking as someone else who had this issue with the same hardware/distro > combination, switching to UXA appears to have eliminated the corruption. I'm afraid switching to UXA didn't solve the problem. OS: Ubuntu 13.10 Kernel: Linux foobar 3.11.0-13-generic #20-Ubuntu SMP Wed Oct 23 17:26:33 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) I have random single char corruption with all three - EXA, UXA and SNA - acceleration methods. I didn't see any notable difference. I will test it with older kernels soon.
(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.
Do any of you smart kernel-guys have any clue which package in Ubuntu might be responsible for something like this? We're having difficulty getting our issue in front of the right set of eyes: https://bugs.launchpad.net/bugs/1227569
Closing due to age. Please reopen if problem persists.