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.
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