diff options
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index e1496b79c28a..2a952fcb1516 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -693,7 +693,11 @@ unsigned long native_calibrate_tsc(void) switch (boot_cpu_data.x86_model) { case 0x4E: /* SKL */ case 0x5E: /* SKL */ - crystal_khz = 24000; /* 24 MHz */ + crystal_khz = 24000; /* 24.0 MHz */ + break; + case 0x5C: /* BXT */ + crystal_khz = 19200; /* 19.2 MHz */ + break; } } @@ -895,6 +899,8 @@ int recalibrate_cpu_khz(void) tsc_khz = x86_platform.calibrate_tsc(); if (tsc_khz == 0) tsc_khz = cpu_khz; + else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz) + cpu_khz = tsc_khz; cpu_data(0).loops_per_jiffy = cpufreq_scale(cpu_data(0).loops_per_jiffy, cpu_khz_old, cpu_khz); @@ -1302,8 +1308,16 @@ void __init tsc_init(void) cpu_khz = x86_platform.calibrate_cpu(); tsc_khz = x86_platform.calibrate_tsc(); + + /* + * Trust non-zero tsc_khz as authorative, + * and use it to sanity check cpu_khz, + * which will be off if system timer is off. + */ if (tsc_khz == 0) tsc_khz = cpu_khz; + else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz) + cpu_khz = tsc_khz; if (!tsc_khz) { mark_tsc_unstable("could not calculate TSC khz"); |