[GM42] Screen flickering due to false SVIDEO detection

[Alexander Myshov]

[Report]

After logging in and boot time screen flickers multiple times. Flickering also after showng notification of connecting with wi-fi network first time. Same problems was on 12.04 while wine applications was working (but I've not tested wine apps on 13.04 yet).

Video record of issue: http://www.youtube.com/watch?v=vdgMgHHaW74

Powersave quirck from that bug https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/538648 is not working for me.

I have HP Probook 4510s D40 AM5. Ubuntu 13.04 (32-bit).

I made research with google and found pretty much similar problems but not exactly as my. Like that:
http://www.kubuntuforums.net/archive/index.php/t-58588.html
https://bbs.archlinux.org/viewtopic.php?id=150875
http://forums.linuxmint.com/viewtopic.php?f=59&t=106061
and many bugs on launchpad of course.

[Chris Wilson (ickle)]

What I suspect this is a display FIFO underrun. Can you please append drm.debug=6 to your kernel command line (via grub) and attach a dmesg from after you see flicking?

[Alexander Myshov (myshov)]

Ok I did what you ask. I execute dmesg after 10 sec when flickering is gone.

[Alexander Myshov (myshov)]

I think that info also will be useful. What I find out additionaly is that screen regulary flickering after switching from virtual terminal to X (Ctrl+Alt+F1, Ctrl+Alt+F7, Ctrl+Alt+F1, Ctrl+Alt+F7).

[Chris Wilson (ickle)]

There are a few underruns reported there, just not as many as I expected. What is strange though are the attempts to probe a TV. Can you try testing video=SVIDEO-1:d (again append to the kernel commandline) and seeing if that prevents the flicker?

[Alexander Myshov (myshov)]

Always works fine now. This option solved the problem. But I want to help solve this problem for another users. How can I help with debugging this issue?

[Chris Wilson (ickle)]

So the issue is the false SVIDEO detection then. The g4x silicon was quite flaky with its TV detection, but I thought we had it stable now.

Firstly: does your hardware even have an SVIDEO connector (composite out)?
Can you please attach the drm.debug=6 dmesg from boot so that we can see the debug output for connector initialisation (basically to see what the BIOS says is on the machine)? One answer may be just to quirk your machine to stop it claiming it has SVIDEO in the first place, as the false positive in the detection could easily be due to a floating pin on the motherboard.

[Daniel Hähnke (haehnke)]

Adding "video=SVIDEO-1:d" to the kernel command line also fixed this issue for me.

Samsung P210-Pro P8400 Padou with Intel GMA X4500 graphics.

[penalvch (penalvch)]

Alexander Myshov, 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

[Launchpad Janitor (janitor)]

[Expired for xserver-xorg-video-intel (Ubuntu) because there has been no activity for 60 days.]