From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nate Lawson Subject: RE: can't switch CPU frequency while running on batterypower Date: Tue, 6 Jan 2004 13:39:44 -0800 (PST) Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Message-ID: <20040106133725.E27491@root.org> References: <3ACA40606221794F80A5670F0AF15F8401720C76@PDSMSX403.ccr.corp.intel.com><32908.192.168.36.2.1073412456.squirrel@defiant.homedns.org> <20040106103944.Q26693@root.org> <32785.192.168.36.2.1073420997.squirrel@defiant.homedns.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <32785.192.168.36.2.1073420997.squirrel-4AGA6j5e2AhmdDG0eupGX0B+6BGkLq7r@public.gmane.org> Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Defiant Cc: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-acpi@vger.kernel.org On Tue, 6 Jan 2004, Defiant wrote: > Nate Lawson wrote: > > This is most likely a problem with re-evaluation of _PSS after it has been > > changed. I don't remember if Linux uses the notify on the processor > > object to re-evaluate _PSS. If Linux does this correctly, it may be that > > the underlying firmware has a bug and you should use a more specific > > cpufreq driver (i.e. SpeedStep or whatever). Some systems have a problem > > where they don't properly export firmware information to the ACPI > > performance states interface. > > uhm, I don't know why, but it is working now, using > CONFIG_X86_P4_CLOCKMOD instead of CONFIG_X86_SPEEDSTEP_ICH, even it is a > Pentium 4m, not Pentium 4. Sure. In general, it's better to use a hw-specific cpufreq driver instead of the generic ACPI one, even if the latter seems to work. Many chipsets don't export the hw-specific information to ACPI correctly and thus ACPI performance states cpufreq should be a last resort. If they still don't work, you should try multiple hw-specific drivers, as you did. -Nate ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click