Kernel Build FAQ
From Parvi - Open source software and patches
Can I run a 2.4.x kernel on my Cobalt?
Yes! RaQ 550 systems ship with a 2.4.x kernel already, and need no special preparations. All the other systems ship with a 2.2.x kernel, and need their ROMs updated to ready them for a 2.4.x kernel.
Can I run a 2.6.x kernel on my Cobalt?
Yes, with a little work you can. After updating your ROM you should have no problems booting a 2.6.x kernel.
How do I patch my kernel with your patch?
Provided the patch is in the your kernel source directory and you are too, you'd do:
# patch -p1 < [patch]
Do I have to patch my kernel?
Straight up? No*. If you do though, you get the LCD/front panel drivers, access to extra facilities offered by Cobalt hardware, including, but not limited to:
- System sensors
- Memory configuration
- System serial number (useless, I know)
- System type
- ACPI support
* - In kernel version 2.6.12, the eepro100 driver is broken. I've fallen back to its successor, the e100 driver. However, the e100 driver is extra strict regarding the controller ROM checksum. A kernel patch is required to remove this "behavior".
What happens if hunks fail?
You can try to add some fuzz to "patch", help it find what it's looking for. This is done by adding "-f 5" after "-p1". If it still fails, send me an email with the exact kernel version you're try to compile, the version of my patch you're using, and a list of any other patches you previously applied to the kernel source.
What should I include in my kernel config?
The answer varies for each Cobalt, and the answers are long. So, I'll be answering this in a seperate document which I've yet to write.
I'm lazy, ok, not too lazy... I've configured my kernel, now what?
Just do the following:
# make vmlinux modules modules_install # strip vmlinux # bzip2 vmlinux # cp vmlinux.bz2 /boot/
All done.
I'm compiling a kernel, but the build complains about "as86: Command not found"!
Don't build a bzImage. Cobalt's boot from a gzipped or bzip2ed vmlinux.
I've built my kernel, how should I compress it?
bzip2 tends to offer a slightly better compression when it comes to kernels. The following command works:
# bzip2 vmlinux
Is there any size restriction on my kernel?
Yes, but it's workable. Your kernel can be no larger than 1800KB compressed.
How can I get my kernel down to size?
Start by lopping out support for devices that are not in the system. You might want to choose a specific I/O scheduler (I prefer the deadline scheduler). Build modules where possible. Every little bit helps.