Bug#678116: linux: Please backport x86 CPU driver autoprobing from Linux 3.4 to 3.2
Dear Debian folks,
»x86 CPU driver autoprobing« was merged to Linux 3.4 .
There's a growing number of drivers that support a specific x86
feature or CPU. Currently loading these drivers currently on a
generic distribution requires various driver specific hacks and
it often doesn't work. For example a common issue is not loading
the SSE 4.2 accelerated CRC module: this can significantly lower
the performance of Btrfs which relies on fast CRC. Another issue
is loading the right CPUFREQ driver for the current CPU.
Currently distributions often try all all possible driver until
one sticks, which is not really a good way to do this.
Linux already has autoprobing mechanisms for drivers, based in
kernel notifications and udev. In this release, Linux adds auto
probing support for CPU drivers, based on the x86 CPUID
information, in particular based on vendor/family/model number
and also based on CPUID feature bits. Code: (commit 1), 2, 3, 4,
5, 6, 7, 8, 9)
This feature would also make `cpufrequtils`  currently shipping an
init.d script for loading the CPUFREQ driver  obsolete for x86 based
Since Debian Wheezy is going to ship Linux 3.2 the recommendation gotten
on systemd-devel to use a newer Linux kernel  do not help much. It
would be great if that feature could be backported. Probably all
distributions shipping Linux 3.2 are interested in this so it would be
great if that could be done at the upstream stable Linux 3.2.