Linux-SWAT: Created page with "= Kernel: to recompile or not to recompile ? = * You don't have to if you don't need to add a new feature. * You don't have to if there's no urgent security kernel update. * I..."

2012-11-28T01:38:26Z

Created page with "= Kernel: to recompile or not to recompile ? = * You don't have to if you don't need to add a new feature. * You don't have to if there's no urgent security kernel update. * I..."

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= Kernel: to recompile or not to recompile ? =
* You don't have to if you don't need to add a new feature.
* You don't have to if there's no urgent security kernel update.
* If you want to acquire a lot of global Linux knowledge, or if you are just curious, then yes, just go for it.

= Is it simple or complicated to recompile ? =
* Both.
* But as there's a default kernel configuration file for Open Pandora, it's pretty easy.

= Downloading and pre-configuring the latest kernel sources =
* Plug the net, be root, then:
mkdir -p /usr/src/
cd /usr/src/
git clone git://openpandora.org/pandora-kernel.git
ln -s pandora-kernel linux
cd pandora-kernel
git checkout --track -b pandora-3.2 origin/pandora-3.2
make omap3_pandora_defconfig

= The fun part: tweaking =
* The configuration is stored in a hidden file named /usr/src/linux/.config
* You can use many tools to edit the configuration.
* The kamikaze way: edit manually the .config . Don't do that.
* The lazy way: install KDE and use:
make xconfig
* The common way, which i recommend:
make menuconfig

= Menuconfig =
* Kernel options are stored in a tree.
* Options can be marked as [*] built-in, or <M> module.
* The vast majority of those options refers to a driver or a functionality.
* Built-in means inside the kernel, so once the kernel boots, you can't remove or change parameters.
* Module means you can either add or remove them after the boot. Ever typed "modprobe ehci-hcd" ?
* The exemple below is copied from my PC, will copy the real OP one later.
Arrow keys navigate the menu. <Enter> selects submenus --->. Highlighted letters are hotkeys. Pressing <Y> includes, <N>
excludes, <M> modularizes features. Press <Esc><Esc> to exit, <?> for Help, </> for Search. Legend: [*] built-in [ ]
excluded <M> module < > module capable
[*] DMA memory allocation support
General setup --->
[*] Enable loadable module support --->
[*] Enable the block layer --->
Processor type and features --->
Power management and ACPI options --->
Bus options (PCI etc.) --->
Executable file formats / Emulations --->
[*] Networking support --->
Device Drivers --->
Firmware Drivers --->
File systems --->
hacking --->
options --->
Cryptographic API --->
Virtualization --->
Library routines --->
<Select> < Exit > < Help >

= A simple tweak =
* Highlight Cryptographic API --->
* Push [enter]. You're now in the Cryptographic API section.
* With [space], select all cryptographic algorithms you can. Ensure they are marked as <M>, not <*>.
* With [right], select < Exit >, then push [enter].
* Again, with [right], select < Exit >, then push [enter].
* Now push [enter], saying <Yes> to "Do you wish to save your new configuration ?".
* You're now ready to compile a kernel which will drive James Bond angrily jealous.

= Kernel compilation =
* Be sure you've overclocked your OP to the maximum MHz.
* At 800MHz, it's a 3+ hours job.
* Now you can compile it with:
cd /usr/src/linux/
make clean
make uImage
make modules
make modules_install
rm /boot/uImage
cp arch/arm/boot/uImage /boot/uImage
* Reboot.

= Speed up the compilation time using two or more Pandoras =
* Read [http://pandorawiki.org/Software_projects/OS/Slackware/Advanced_usage/Distributed_compilation this], and set up your Pandoras.
* Then compile, replacing previous related commands with:
make -j4 CC=distcc uImage
make -j4 CC=distcc modules
In the -j(n), n represents the (number of CPU used X 2), so if you compile with 10 OP, it will be -j20 .

= 3D driver =
* As it's not open source, you have to grab it on the Texas Instruments website.
* More on this later.

[[Category:Development]]
[[Category:Slackware]]
[[Category:Software]]
[[Category:System]]

Software projects/OS/Slackware/Advanced usage/Kernel-13.37 - Revision history

Linux-SWAT: Created page with "= Kernel: to recompile or not to recompile ? = * You don't have to if you don't need to add a new feature. * You don't have to if there's no urgent security kernel update. * I..."