I have been working with linux (all kinds of distributions, trying them out). This is something I just started having problems with, but it wasn't happening previously. I booted into Backtrack (live cd), and that had been working fine for a couple weeks. Odd thing is, i started up X with startx, and it boots into KDE just fine, except right before it is done loading (when the music starts playing) the backlight seems to go out. It is fine all the way up to that point. I rebooted, went into fluxbox, doesn't happen. Fluxbox runs fine, backlight stays.

I also have slackware installed on the hard drive. I just recently compiled the kernel, 2.6.13.20, and everything went smoothly, except the same problem when logging into KDE. Again, fluxbox runs fine. I haven't installed gnome yet (what i use anyways) but this was a new install. Why would this start on both of them just tonight? Before this, it booted into KDE perfectly fine with the Live cd and the slackware installation. Just after compiling the kernel, it started, which I can't see how that could affect the live cd.

Anybody have any ideas what could cause this? I am going to install gnome on the slackware install, and see if it happens there. Is it somethign to do with ACPI.

By the way, its a Sony Vaio PCG-K23.

Thanks in advance!

Looks like kde is switching your backlight off ... does this happen at the kdm stage or when you login?

You could see what happens when you switch acpi off.

After KDM. I choose KDE, type in username and password. and then I get the first few seconds, but once it starts the whole initialization, it goes out. But why would it be working OK with the Live CD, then stop there. Just seems odd. Oh well, I'll try turning ACPI off. See if it helps. Thanks for the reply.

You could try comparing the login script for kde on the live CD with that for the installed version. (Also - try logging into kde as root.)

Since I am having the same problems on both, I don't see how comparing the scripts could help. Doesn't matter if I am root or a user, same issue. The odd thing is, I haven't changed anything but compiling the new kernel for slackware on the HDD. Nothing has changed on the livecd. Nothing changed in the computers configuration (BIOS or anything like that). I didn't have KDM enabled at first, just doing startx (along with the live cd). Only happens with KDE though. XFCE, fluxbox, blackbox, fvwm, all fine. Just KDE. I could see if it was just the slackware installation after the kernel change, but on the live cd too? Baffling me to no end.

Seems to be the ACPI thing. Must be buggy since I enabled it in the kernel during the recompile. Still seems odd it would affect the LiveCD, but oh well. Thanks for the tips!