Commit 532cfee6 authored Jun 11, 2009 by Naga Chumbalkar Committed by Dave Jones Jun 15, 2009

[CPUFREQ] powernow-k8: read P-state from HW

By definition, "cpuinfo_cur_freq" should report the value from HW. So, don't
depend on the cached value. Instead read P-state directly from HW, while
taking into account the erratum 311 workaround for Fam 11h processors.

Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Langsdorf, Mark <mark.langsdorf@amd.com>
Cc: Thomas Renninger <trenn@suse.de>

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Reviewed-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Langsdorf, Mark <mark.langsdorf@amd.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>

parent b394f1df

arch/x86/kernel/cpu/cpufreq/powernow-k8.c

+11 −14

Original line number	Diff line number	Diff line
		@@ -118,20 +118,17 @@ static int query_current_values_with_pending_wait(struct powernow_k8_data *data)
		u32 i = 0;

		if (cpu_family == CPU_HW_PSTATE) {
		if (data->currpstate == HW_PSTATE_INVALID) {
		/* read (initial) hw pstate if not yet set */
		rdmsr(MSR_PSTATE_STATUS, lo, hi);
		i = lo & HW_PSTATE_MASK;
		data->currpstate = i;

		/*
		* a workaround for family 11h erratum 311 might cause
		* an "out-of-range Pstate if the core is in Pstate-0
		*/
		if (i >= data->numps)
		if ((boot_cpu_data.x86 == 0x11) && (i >= data->numps))
		data->currpstate = HW_PSTATE_0;
		else
		data->currpstate = i;
		}

		return 0;
		}
		do {