> > Will you please attach the output of acpidump on the machine with the > > core i7 cpu? > > Please attach the output of every file > > under /sys/firmware/acpi/tables/dynamic/SSDT*? > > cat /sys/firmware/acpi/tables/dynamic/SSDT1> ssdt1 > > > > Please also attach the output of /proc/cpuinfo. > Thank you for your attention. This specific issue has already been solved for > me, it turns out be yet another bios issue (as I have experienced before). > Enable base clock setting and all C states are gone! > > But now I have a few other issues that maybe you can help me with: > > - How are intel core i7 C states mapped to linux C states? Both my laptop > (core2duo T9300) and desktop (core i7 920) should have c1-c3-c6-c7, but on > both machines linux only sees c1-c2-c3. It is up to the BIOS to map hardware C-states to software visible C-states. How the BIOS does that would be answered by the information that Yakui requested above. In particular, most BIOS today use the _CST object in the DSDT or in an SSDT. > - On said desktop, I see no difference in power consumption with c states > enabled or disabled; if they're enabled (and base clock control is off...) > linux is using c3 almost all of the time, but power consumption remains the > same (about 110 watts for the complete motherboard, is that normal?). No, that isn't normal. C-states on modern processors generally save a lot of energy. If you run powertop and you find that you are over 99% idle and you save no energy compared to when you are 0% idle (say a copy of "cat /dev/zero > /dev/null" for each core) then something is wrong with your system. > - From a quick inspection of the acpi tables (I am not quite an expert on > this...) it looks like a number of _CST objects are exported with default bios > settings, while with base clock control enabled, these are gone. I would to > try (yes I know, not recommended, etc.) to copy the _CST objects from the one > boot instance's tables to the other. Now I think of it, it would probably even > suffice to boot one time with baseclock control disabled, record the acpi > tables (SSDT?) and then make the kernel use that in subsequent boots with the > base clock control enabled (with all other bios settings the same, off > course). Is that difficult to achieve? I seem to remember that's possible one > way or another. It is possible, but as soon as you reverse engineer and over-ride something in the BIOS, you are on very thin ice. Presumably the BIOS engineer made a concious decision to disable C-states when you over-clock your board and had a reason to do so. Maybe the more important question is what measurable benefit you get when you over-clock your board, and if you really need that... -Len Brown Intel Open Source Technology Center -- 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
