Kubuntu X configuration for old intel chipsets

[Guest]

Good evening,

I'm testing a new text based installer for any *buntu based distros called OBI. It's very simple and works well even on old P3 machine with as little as 128mb ram. To work need just an USB and a tarball with the distro you like. The setup is normally based on OEM install. If you're interested in have a look on Ubuntu Wiki:

https://wiki.ubuntu.com/phillw/OBI

With such a tool I'm experimenting all the ubuntu based distributions I found and obviously Kubuntu too.
I'm testing on an old notebook 12", a C400 from Dell with a Pentium III Mobile 866mhz processor and 768Mb ram and even with those low specs all works fine. But I have found a problem with xorg configuration, well more precisely I didn't. Let me explain:
to use a live cd on my old notebook I need to create a persistent USB, boot the first time and quickly switch to a console to create the xorg.conf file with uxa or my system will hangs (randomly).On the next reboot I've no problems installing. And is much more convenient than decompressing squashfs and modify it for my needs for every iso! This time when I installed Kubuntu I forgot to create the file and my system didn't hangs. To do a quick check I tried to install xubuntu without the hack and the system hanged in less than 5 minutes. Twice.
Beside this let me tell you I used to have problems with dithering on my old i830 chipset under Ubuntu since the 6.06, where linux seems to not handle well the 24bit and this leads to noticeable banding (less with uxa, indeed). Well, this issue is completely absent on kubuntu!
As far as I know Kubuntu is still using X display manager for the video, Wayland will start to be the default from 14.04. So technically we are on the same boat.

Due to my new assignment to Xubuntu QA (before was Lubuntu QA) I would like to have some infos about how Kubuntu is configuring the video output to see if I can implement the same solution for old intel chipset without forcing to use uxa accelmethod on xorg. At this time I'm not sure if is kwin managing all, I do apologize but I never use KDE before.

An help will be much appreciated. Thanks!

F.

[SteveRiley]

As far as I know Kubuntu is still using X display manager for the video, Wayland will start to be the default from 14.04. So technically we are on the same boat.

Yes, Kubuntu is still using the X display server. Kubuntu won't see Wayland until 14.10.

A display manager is the thing that presents a graphical login screen. It's started by init (PID=1), spawns the X server, and owns the desktop.

I used to have problems with dithering on my old i830 chipset under Ubuntu since the 6.06, where linux seems to not handle well the 24bit and this leads to noticeable banding (less with uxa, indeed). Well, this issue is completely absent on kubuntu!

I'd attribute this to KWin, KDE's window manager. KWin is more mature than the handful of window managers that Ubuntu and the Gtk-related flavors have used over the years.

I would like to have some infos about how Kubuntu is configuring the video output to see if I can implement the same solution for old intel chipset without forcing to use uxa accelmethod on xorg. At this time I'm not sure if is kwin managing all

As to why KDE doesn't hang but the other DEs do, I wonder if the difference is more related to choice of display managers (KDM vs. GDM) or the greeters in LightDM (KDE vs. Gtk or Unity). I could be completely wrong here, though. I suggest that you take this question to #kubuntu-devel on IRC; the Kubuntu developers themselves are probably best-equipped to answer your question.