Messages in this thread | | | Date | Thu, 19 Feb 2009 11:54:06 +0000 | Subject | Re: [PATCH] cpufreq: Change link order of x86 cpufreq modules | From | Alan Jenkins <> |
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On 2/18/09, Ingo Molnar <mingo@elte.hu> wrote: > > * Matthew Garrett <mjg59@srcf.ucam.org> wrote: > >> On Wed, Feb 18, 2009 at 07:31:37PM +0100, Ingo Molnar wrote: >> >> > Nice fix! Where does this information come from? Distro module >> > ordering magic? It's rather non-trivial. >> >> Pretty much. p4-clockmod is never the preferred option because >> it does no voltage scaling. speedstep-centrino is now almost >> entirely functionally replaced with acpi-cpufreq. The >> powernow-k8 issue was a personal communication from davej. > > I'm wondering whether that priority order should/could be > expressed in the module space too - so that distros wouldnt have > to replicate this. This is really a piece of information the > kernel is best at maintaining.
The latest development version of module-init-tools (in the git tree) is designed to preserve the kernel link order when resolving builtin aliases. If you have two modules which provide the alias "pci:123", they will be loaded in the same order as if they were builtin drivers.
It should work if all the cpufreq drivers provide an alias "cpufreq-driver" and userspace just does "modprobe cpufreq-driver". You just need to be sure none of the cpufreq drivers provide *other* aliases which cause them to be loaded earlier, by udev or some other bootscript.
Alan
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