Messages in this thread | | | Date | Wed, 22 Mar 2006 06:57:14 +0100 | From | Edgar Toernig <> | Subject | Re: p4-clockmod not working in 2.6.16 |
| |
Dave Jones wrote: > > Fix the code to disable freqs less than 2GHz in N60 errata. > > - else if (has_N60_errata[policy->cpu] && p4clockmod_table[i].frequency < 2000000) > + else if (has_N60_errata[policy->cpu] && ((stock_freq * i)/8) < 2000000)
Doesn't change anything here - I still get _all_ frequencies where I think I shouldn't:
| processor : 0 | vendor_id : GenuineIntel | cpu family : 15 | model : 2 | model name : Intel(R) Pentium(R) 4 CPU 3.00GHz | stepping : 9 | cpu MHz : 3000.000 [same for cpu 1, it's a single P4 with HT]
Looks like the f29 cpu that should have the errata.
| > cat /sys/devices/system/cpu/cpu1/cpufreq/scaling_available_frequencies | 375000 750000 1125000 1500000 1875000 2250000 2625000 3000000
| > dmesg|fgrep clockmod | p4-clockmod: P4/Xeon(TM) CPU On-Demand Clock Modulation available
Further: the directory cpufreq in /sys is there only for cpu1 - not for cpu0:
| > ls /sys/devices/system/cpu/cpu? | /sys/devices/system/cpu/cpu0: | topology | | /sys/devices/system/cpu/cpu1: | cpufreq topology
And at last: reading Intel's errata it should be good enough to not go below 25% instead limiting all below 2GHz. I'm not even sure whether the 2GHz mentioned there is the reduced or the nominal clock. Running 2GHz on 12.5% would be a really fast CPU.
| N60. Processor May Hang under Certain Frequencies and 12.5% | STPCLK# Duty Cycle | | Problem: If a system de-asserts STPCLK# at a 12.5% duty cycle, the | processor is running below 2 GHz, and the processor thermal | control circuit (TCC) on-demand clock modulation is active, | the processor may hang. This erratum does not occur under | the automatic mode of the TCC. | | Implication: When this erratum occurs, the processor will hang. | | Workaround: If use of the on-demand mode of the processor's TCC is desired | in conjunction with STPCLK# modulation, then assure that STPCLK# | is not asserted at a 12.5% duty cycle.
Ciao, ET. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |