[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>

1 files changed, 5 insertions, 8 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
index 10baa3501ed3..18c8b67ea3a7 100644
--- 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;