On Fri, 18 Jan 2013 13:32:33 +0100 André Przywara <andre@xxxxxxxxx> wrote: > On Fri, 18 Jan 2013 12:37:17 +0100 > Borislav Petkov <bp@xxxxxxxxx> wrote: > > (updating Matthew's email as per MAINTAINERS) > > > On Thu, Jan 17, 2013 at 07:40:44PM -0600, Leonid Isaev wrote: > > > Arrh, modprobe still does not exit cleanly with this... > > > > As I said already above: > > > > >> That's correct - we say ENODEV on your CPU which supports hardware > > >> P-states and hand off to acpi-cpufreq which has that functionality > > >> now. > > > > It is supposed to work that way: we return an error from the > > powernow-k8 init function so that it doesn't load but hand off to > > acpi-cpufreq so that it gets loaded instead. > > > > > > But, we also have the CPU autoprobing deal: > > > > > > > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=644e9cbbe3fc032cc92d0936057e166a994dc246 > > > > > > > > so, *actually*, powernow-k8 should be loaded by default. I dunno, > > > > maybe upgrade udev on your distro? > > > > > > Udev 196 and 197 + linux <= 3.6.11 yield correct CPU autoprobing. > > > However, udev 197 + linux 3.7.2 do not. I haven't tested udev 196 > > > with 3.7.2 though, but it does not look like a udev issue. > > > > Hmm, I'll bet this has something to do with the fact that HW_PSTATE is > > in another CPUID function on AMD than on Intel and udev doesn't see > > that bit to load acpi-cpufreq automatically. > > But the acpi-cpufreq does not export it's dependency on some CPUID > flags, since it is an _ACPI_ module. Shouldn't the load be triggered > while parsing the ACPI tree instead? > > $ /sbin/modinfo drivers/cpufreq/acpi-cpufreq.ko | grep alias > alias: acpi > > $ /sbin/modinfo drivers/cpufreq/powernow-k8.ko | grep alias > alias: x86cpu:vendor:0002:family:000F:model:*:feature:* > > How does ArchLinux loads acpi-cpufreq on Intel CPUs? It should now be > the same mechanism on AMD. Or does it have acpi-cpufreq somehow > hard-coded in the scripts for GenuineIntel? In both cases Intel and AMD we rely on the kernel/udev autoprobing to insert correct CPU and KVM drivers, i.e. there are no custom scripts or manual loading of modules via systemd. However, in Intel's case acpi_cpufreq is loaded correctly (and always has been). Indeed, on an Intel core2duo: $ dmesg | grep -i cpufreq [ 9.005851] ACPI: Requesting acpi_cpufreq > > Regards, > Andre. Sincerely, L. -- Leonid Isaev GnuPG key: 0x164B5A6D Fingerprint: C0DF 20D0 C075 C3F1 E1BE 775A A7AE F6CB 164B 5A6D
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