Hi Thomas. Thanks for the message. On Wed, Sep 1, 2010 at 11:40 PM, Thomas Renninger <trenn@xxxxxxx> wrote: > On Sunday 29 August 2010 06:54:44 Tiago Marques wrote: >> Hi, >> I'm having a problem with this processor not having frequency steps >> and apparently only voltage steps. I find it very strange but that's >> what Intel's documentation suggests. I can't load acpi-cpufreq because >> it doesn't find any device and battery life in linux is suffering >> around 20% less due to this. > Where do you have the 20% info from, I doubt you verified it? Yes. Since it seems no one can't return Windows licenses for refunds anymore, I have went ahead and booted windows on it, without any driver installed and just configured it to have frequency scaling working, which in this case is only voltage scaling. I measured almost 6 hours of battery life and the processor & chipset frequently had the fan stop when idling. In linux, in the same conditions, I got less than 4 hours and the fan never stops. I configured a PCI-express power saving feature on the kernel and it seems to have dropped noise a bit. Battery life is still not great and the fan still never stops. I'm trying to find something with which I can measure the actual power going through the AC adapter but for now battery life tests is pretty much all I can do. The 20% figure is obviously optimistic since I'm accounting a positive effect from the PCI-Express power saving feature to not quote 33% less. > >> I have confirmed that the CPU supports >> Speedstep, just this very strange variation. > You are not the only one: > https://bugzilla.kernel.org/show_bug.cgi?id=16072 > [HP Pavilion dm1-1110ev] Cpufreq doesn't work at all ( Intel Celeron U2300 ) > or the last comments (or search for U2300) here: > http://software.intel.com/en-us/articles/enhanced-intel-speedstepr-technology-and-demand-based-switching-on-linux/ > >> Can I somehow help with this to get it fixed? Who are the current maintainers? > Not exporting cpu frequencies seem to be intended for this cpu for whatever reasons. It doesn't have more than one. I checked in windows and I also can't change frequency, despite reports from a person on the contrary: http://scottiestech.info/2010/02/05/how-to-increase-your-laptops-battery-life-a-lot-with-crystalcpuid/ I have confirmed that the GM45 chipset doesn't support frequency scaling of the FSB on Intel's datasheet, so the speed he reports of 98MHz is a bug. I found similar frequencies upon use. Since I performed my tests with LCD brightness in full, that would account for the one hour difference on the best result, while the less than four hours he also reports may be due to speedstep not working before he messed with configurations. I tried the same program and the CPU is locked at 6x, although the voltage isn't, it's somewhere from 0.925 to 1.075v if I recall correctly. > If you have efficient C-states, frequency states are not that important. I know. But what about voltage? Intel's datasheet clearly states this processor supports two voltage states, I guess for the purpose of relaxing clock binning requirements for these CPUs. I'm thinking it does scale when in windows. The Pentium SU4100 has similar problems but he allows one p-state, from 1300MHz to 1200MHz. I can't seem to find the lowest multiplier available on these platforms, CrystalCPUID lists mine as 6x, hence 1200MHz. I thought Core 2's could idle at something like 800MHz and I find it strange that this one can't also. > You could try msr-tools to access frequency switching MSRs directly. > But you need to know the supported frequencies. Intel generally publishes > such documentation for all of their released CPUs. > > You could then try to set the frequency by: > FREQUENCY="max/min_freq_from Intel spec" > modprobe msr > wrmsr --processor X 0x199 $FREQUENCY > > This is not a solution, but you could figure out whether switching works > at all and if, you could test whether you really have 20% more of battery life time, > but I expect you won't get that much. That probably won't work, given my tests in windows. Can I do that for the voltage also? I also tried the linux-phc modules for debugging but it also doesn't load. Best regards, Tiago > > Thomas > -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
