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Commit c70ca00f authored by Ben Collins's avatar Ben Collins Committed by Dave Jones
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[CPUFREQ] p4-clockmod: Workaround for CPU's with N60 errata 



Ignore clock frequencies below 2Ghz for CPU's detected with N60 errata bug.

Signed-off-by: default avatarBen Collins <bcollins@ubuntu.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent cdc9cc1d

arch/i386/kernel/cpu/cpufreq/p4-clockmod.c

+9 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ enum { 




static int has_N44_O17_errata[NR_CPUS];

static int has_N60_errata[NR_CPUS];

static unsigned int stock_freq;

static struct cpufreq_driver p4clockmod_driver;

static unsigned int cpufreq_p4_get(unsigned int cpu);
@@ -226,6 +227,12 @@ static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy) 
	case 0x0f12:

		has_N44_O17_errata[policy->cpu] = 1;

		dprintk("has errata -- disabling low frequencies\n");

		break;



	case 0x0f29:

		has_N60_errata[policy->cpu] = 1;

		dprintk("has errata -- disabling frequencies lower than 2ghz\n");

		break;

	}

	

	/* get max frequency */
@@ -237,6 +244,8 @@ static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy) 
	for (i=1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {

		if ((i<2) && (has_N44_O17_errata[policy->cpu]))

			p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;

		else if (has_N60_errata[policy->cpu] && p4clockmod_table[i].frequency < 2000000)

			p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;

		else

			p4clockmod_table[i].frequency = (stock_freq * i)/8;

	}