Weird artefacts in console mode

Havin_it · Posted: Fri Sep 21, 2007 5:43 pm Post subject: Weird artefacts in console mode

Hi,

Hope someone can shed some light on this for me. It's been happening for a while now, so not much hope of tracing it to any particular package upgrade I'm afraid

When I shut down, after KDM stops and I drop back to console mode, 90% of the time I get some garbage on the screen. The artefacts consist (AFAICT) of the top of a character of console text, with the pixels from a single row in the character repeated in a vertical stream down the screen. The artefact (there's only ever one) appears fully-formed when I drop out of X, and does not move throughout the shutdown process. The scrolling console-text is visible directly adjacent to it, but if there is more than one "streamed" pixel then nothing shows between them. It can start anywhere below a level about halfway up the screen.

Yesterday I did a heavy update job, which I started in a screen session inside KDE, then detached the screen and vt-switched to vt1, quit KDM and reconnected to the running screen session. There was one of these artefacts on-screen when I vt-switched, and later, as the job was continuing to run, more text got "trapped" within a rectangle surrounding the original artefact until I had an approx. 2cm(h)x3cm(w) rectangle of white at the foot of my screen.

Pertinent info:
Graphics: Intel 852/855GM
Desktop: KDE + compiz-0.5.0 + compiz-extras-0.5.0.2 (not from portage)

emerge --info:

My_World · Posted: Fri Sep 21, 2007 6:16 pm Post subject:

Have you tried different framebuffer resolutions in the kernel?
Default to 1024x768@60 to see if it helps.
_________________
"Ubuntu" - an African word meaning "Gentoo is too hard for me".

Havin_it · Posted: Sun Sep 23, 2007 10:27 pm Post subject:

Cool, that seems to have helped. I didn't have the VESA device enabled at all before (which is where I found a default resolution setting so I assume that's what you meant), I enabled it and set my 1024x768@60, and so far I haven't seen any of these artefacts again. I also haven't had any X lockups on exiting from KDM either, so maybe this is a bonus result...!

Hey, I wonder if my TV-out works now? (Will test shortly but I'm ready for disappointment)

Havin_it · Posted: Wed Oct 24, 2007 10:22 am Post subject:

Waaah! Just when I was enjoying much better stability, I upgraded to kernel-2.6.23-gentoo and suddenly the framebuffer resolution setting doesn't seem to be there anymore! So, back where I started, 600x800 framebuffer, frequent freezes and/or artefacts on shutdown.