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Commit 13424f65 authored by Venki Pallipadi's avatar Venki Pallipadi Committed by Dave Jones
Browse files

[CPUFREQ] acpi-cpufreq: Proper ReadModifyWrite of PERF_CTL MSR 



During recent acpi-cpufreq changes, writing to PERF_CTL msr
changed from RMW of entire 64 bit to RMW of low 32 bit and clearing of
upper 32 bit. Fix it back to do a proper RMW of the MSR.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent 0a4b2ccc

arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c

+5 −8
Original line number Diff line number Diff line
@@ -167,11 +167,13 @@ static void do_drv_read(struct drv_cmd *cmd) 


static void do_drv_write(struct drv_cmd *cmd)

{

	u32 h = 0;

	u32 lo, hi;



	switch (cmd->type) {

	case SYSTEM_INTEL_MSR_CAPABLE:

		wrmsr(cmd->addr.msr.reg, cmd->val, h);

		rdmsr(cmd->addr.msr.reg, lo, hi);

		lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);

		wrmsr(cmd->addr.msr.reg, lo, hi);

		break;

	case SYSTEM_IO_CAPABLE:

		acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
@@ -372,7 +374,6 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy, 
	struct cpufreq_freqs freqs;

	cpumask_t online_policy_cpus;

	struct drv_cmd cmd;

	unsigned int msr;

	unsigned int next_state = 0; /* Index into freq_table */

	unsigned int next_perf_state = 0; /* Index into perf table */

	unsigned int i;
@@ -417,11 +418,7 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy, 
	case SYSTEM_INTEL_MSR_CAPABLE:

		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;

		cmd.addr.msr.reg = MSR_IA32_PERF_CTL;

		msr =

		    (u32) perf->states[next_perf_state].

		    control & INTEL_MSR_RANGE;

		cmd.val = get_cur_val(online_policy_cpus);

		cmd.val = (cmd.val & ~INTEL_MSR_RANGE) | msr;

		cmd.val = (u32) perf->states[next_perf_state].control;

		break;

	case SYSTEM_IO_CAPABLE:

		cmd.type = SYSTEM_IO_CAPABLE;