Hi, On Mon, Oct 30, 2006 at 03:03:53PM -0800, Michael Blakeley wrote: > I've recently been bitten by > http://bugzilla.kernel.org/show_bug.cgi?id=7157 - I also have an HP > nc6400, with bios F.05, and can't downgrade to F.03 because my CPU only > became supported in F.05. While I'm waiting to see if HP will fix this > problem in a future bios rev, I wondered why cpufreq needs any bios > information in the first place? > > This is all well outside my technical expertise, so I'm sure that I'm > misunderstanding the problem - but that's why I'm asking. Basically my > question is: why can't cpufreq interrogate the CPU directly, in order to > find out what sort of cpu frequency scaling it supports (SpeedStep in > various flavors, PowerNow, and whatever else is out there in the wild)? > Wouldn't that be more robust than relying on the bios to get it right? Unfortunately, no -- it is not only a matter of the processor on whether CPU frequency and voltage scaling is supported, but also a matter of the motherboard. Not all combinations of frequencies and voltages which run stable on one notebook may run well on a different notebook with the same CPU. Therefore, such hardcoded table-based approaches are only available in rare cases. Dominik - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
