From: Venki Pallipadi [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 Signed-off-by: Dave Jones Cc: Chuck Ebbert Signed-off-by: Greg Kroah-Hartman --- arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- 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 * 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 cp 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 cp 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; -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/