[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: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>

diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
index 10baa3501ed336c37b5d9a5662ce99484c48d651..18c8b67ea3a75ce4b5d740e1eb8a68b3cda46915 100644 (file)
--- a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -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;