diff options
Diffstat (limited to 'drivers/cpufreq/intel_pstate.c')
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index f6dd1e7..cd9c5f4 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -752,6 +752,29 @@ static struct cpufreq_driver intel_pstate_driver = { static int __initdata no_load; +static int intel_pstate_msrs_not_valid(void) +{ + /* Check that all the msr's we are using are valid. */ + u64 aperf, mperf, tmp; + + rdmsrl(MSR_IA32_APERF, aperf); + rdmsrl(MSR_IA32_MPERF, mperf); + + if (!intel_pstate_min_pstate() || + !intel_pstate_max_pstate() || + !intel_pstate_turbo_pstate()) + return -ENODEV; + + rdmsrl(MSR_IA32_APERF, tmp); + if (!(tmp - aperf)) + return -ENODEV; + + rdmsrl(MSR_IA32_MPERF, tmp); + if (!(tmp - mperf)) + return -ENODEV; + + return 0; +} static int __init intel_pstate_init(void) { int cpu, rc = 0; @@ -764,6 +787,9 @@ static int __init intel_pstate_init(void) if (!id) return -ENODEV; + if (intel_pstate_msrs_not_valid()) + return -ENODEV; + pr_info("Intel P-state driver initializing.\n"); all_cpu_data = vmalloc(sizeof(void *) * num_possible_cpus()); |