In my last post I explained how I installed Ubuntu on the new MacBook AIR 2013. The last issues I have are:
- Sound doesn't work.
- Screen brightness is either 0 (total dark) or 1 (totally lit) after coming back from suspend.
I thought both issues might be kernel related. I also read that actual support for Haswell processors was coming in the 3.11 Linux Kernel so I wanted to give it a try. That's why I started working on compiling the 3.11-rc7 kernel for Ubuntu.
Building the kernel
Building the kernel is really easy. I fetched the sources from the Ubuntu "saucy" repository with the following command:
git clone git://kernel.ubuntu.com/ubuntu/ubuntu-saucy.git |
Before actually building the Kernel, don't forget the apply the patch to add support for the new mouse/keyboard! Then I just copied my current kernel configuration:
cp /boot/config-`uname -r` .config |
I updated the configuration with the new kernel options:
yes '' | make oldconfig make clean |
and I finally build the kernel:
make -j `getconf _NPROCESSORS_ONLN` deb-pkg LOCALVERSION=-custom INSTALL_MOD_STRIP=1 |
- The "-j" option will make sure the build process will use as many CPUs as possible
- "LOCALVERSION=-custom" is used to name your kernel packages with the "-custom" suffix (instead of "-generic")
- "INSTALL_MOD_STRIP=1" is used to remove debug symbols and make the final binaries significantly (10 times!) lighter
When the build is finished, just install the packages (they are created in the parent directory):
dpkg -i *.deb |
Fixing the Wi-Fi
The Wi-Fi uses a proprietary Broadcom driver that will need to be re-compile against this new kernel. Compiling the driver module yourself is a nightmare. Instead, you can simply use the package already available in the "saucy" repository:
https://launchpad.net/ubuntu/saucy/amd64/bcmwl-kernel-source/6.30.223.30+bdcom-0ubuntu3
Reboot and you're all set!
Conclusion
Upgrading to 3.11 does not fix neither the sound nor the brightness problem... or at least not with the rc7. Yet running dmesg you would find an interesting message:
hda-intel Haswell must build in CONFIG_SND_HDA_I915 |
According to what I found on some commit messages, enabling this option in the kernel build configuration might solve the sound issue. I'll try tomorrow and give you an update! If you have any hint on the sound or the brightness issue please let me know.