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| author | Star Zeng <star.zeng@intel.com> | 2016-08-17 10:08:31 +0800 |
|---|---|---|
| committer | Star Zeng <star.zeng@intel.com> | 2016-08-18 12:49:32 +0800 |
| commit | 9430fb3e2a941439e06427558ba19bc7b39d8d49 (patch) | |
| tree | 6a70eac8c48fe2b2efff937c915e1b48cec36dcb /Core/MdeModulePkg | |
| parent | 69f75ff0701e3907af7294f875a1a88528245dba (diff) | |
| download | edk2-platforms-9430fb3e2a941439e06427558ba19bc7b39d8d49.tar.xz | |
PcAtChipsetPkg AcpiTimerLib: Wait 363 ACPI timer counts to get TSC Freq
Compute the number of ticks to wait to measure TSC frequency.
Instead of (ACPI_TIMER_FREQUENCY / 10000) = 357 and 357 * 10000 = 3570000,
use 363 * 9861 = 3579543 Hz which is within 2 Hz of ACPI_TIMER_FREQUENCY.
363 counts is a calibration time of 101.4 uS.
The idea comes from Michael and Paolo.
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul A Lohr <paul.a.lohr@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
(cherry picked from commit a012df5ec643a0c08c2b723a02919a5c9373ca74)
Diffstat (limited to 'Core/MdeModulePkg')
0 files changed, 0 insertions, 0 deletions