OK, this entry is just a reminder for myself.
Install ATI drivers
I followed the instructions at this wiki. For the record, I used method 1, and it worked.
Update: The link above seems dead. Read a a more recent post about Compiz Fusion under Debian Lenny for info on ATI drivers instalation.
Install a SMP kernel
My CPU is an Intel Core 2 Duo T7200... I want a SMP kernel, otherwise I am wasting one of the two cores!
Problem is, the friggin Ubuntu has no 2.6 kernels labeled "SMP". Why, oh why!? OK, I found out: all 2.6.*-686 kernels are actually SMP, even if they don't say anything. If you have 1 CPU, fine. If you have more, they'll be detected at boot time. No more "-smp" in the kernel names.
Wireless with 686 kernel
The default 2.6.15-686 supports the wireless just fine, but installing a 686 kernel (required for SMP, see above) seems to break the wireless. However, the solution is easy. As stated in this Ubuntu forum thread, one just needs to install the "restricted" kernel modules corresponding to her kernel (in my case 2.6.15-27-686):
% aptitude install linux-restricted-modules-2.6.15-27-686
After that, reboot. I guess that the new module is loadable (try modprobe ipw3945), without having to reboot... dunno. Also, if you want to have the restricted modules package upgrade automatically, install linux-restricted-modules-686.
WPA encription for WiFi
Update: Read a more recent article: WPA under Ubuntu/Debian.
Install a 64-bit kernel
OK, installing the mainstream 32-bit Ubuntu was a success. Now I have given Ubuntu amd64 a try (amd64 is for both EM64T (Intel) and AMD64 (AMD)).
Everything went smooth, except installing the ATI drivers (as explained above): the screen froze black when loading GDM. To solve this, I read the troubleshooting section in the link above, and found out that I could either add:
SubSection "extmod" Option "omit XVideo" Option "omit XVideo-MotionCompensation" Option "omit XFree86-VidModeExtension" EndSubSection
to the Section "Modules" of /etc/X11/xorg.conf (beware, it's one OR the other, not both). For me the Load "extmod" did not work, but the SubSection "extmod" did.
Now, for the Xgl thing in 64-bits...
Xgl for 64-bits
I followed the instructions in a previous post, but I found out that some packages were missing, so I manually downloaded them from the Xgl.compiz site. Namely, I downloaded them from the "Edgy" section. However, it didn't work for me :^(
Update: Compiz Fusion under Debian Lenny in a more recent post.