How-to: use custom DSDT in Karmic

[Sentello]

Done, and now?

[s.mulleady1122]

Done, and now?

Well theres nothing more to it. The Frequency of the CPU will automatically go up and down depending on the load, saving power and making the laptop cooler.

[Sentello]

Okay, but still don't working USB, etc. How i fix problem with DSDT?
My DSDT working perfectly in Ubuntu 9.04, but in 10.04 i have some problems... Compiled kernel does not resolve anything

[cyberey66]

For those who want a permanent solutions see this post,

http://swiss.ubuntuforums.org/showpo...2&postcount=66

If you have a patched DSDT and your computer has phoenix bios, you can simply just replace the buggy DSDT in your bios directly.

[spaceballl]

Can someone set me straight? I'm a bit confused...
- What is a DSDT file?
- With the powernow fix in the most recent version of the kernel, do I still need to do modifications to the BIOS / DSDT for the Gateway LT31? Why?
- I've seen so many solutions posted here - all a bit different. what is the best way?
- Any chance all of this will "just work" with the next version of Ubuntu?

[cyberey66]

Can someone set me straight? I'm a bit confused...
- What is a DSDT file?
- With the powernow fix in the most recent version of the kernel, do I still need to do modifications to the BIOS / DSDT for the Gateway LT31? Why?

http://acpi.sourceforge.net/dsdt/index.php
http://forums.gentoo.org/viewtopic.php?t=122145

Basically the DSDT defines the computer hardware configuration including the power saving states of the CPU. There are two compilers to create the DSDT, one from Intel and one from Microsoft. The Microsoft does not comply with the ACPI specifications and is used by many manufacturers.


- I've seen so many solutions posted here - all a bit different. what is the best way?
You have two options; 1. compile each new kernel you use to override the bios with a corrected DSDT you provide, 2. modify your bios to include the correct DSDT and flash it. I personally think the second option is best as it is a permanent and 'proper' fix.


- Any chance all of this will "just work" with the next version of Ubuntu?

Most likely never, the developers expect that the DSDT is written to comply with the standard, which some don't. The developers have also been moving away from overriding the DSDT for ideological reasons. So don't expect future versions to just work. However, if you do modify your bios to include a corrected DSDT, all future versions will 'just work'. I think this is the best path.

I would first, compile the kernel to override the bios with the new DSDT to make sure it works. If it works well, I would then pursue modifying the bios.