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| author | Tom <tomut@yahoo.com> | 2021-02-28 11:47:03 -0700 |
|---|---|---|
| committer | Andreas Kling <kling@serenityos.org> | 2021-03-01 11:11:09 +0100 |
| commit | cdbd878a145c97ffef9ba154071803fdc6c58ac3 (patch) | |
| tree | 8b2ee260f5e0a2a84fc1af5ab271add3a58d03c3 /Kernel/Time/HPET.h | |
| parent | f66adbdd95bc587b9f7971af8b095e11cda0ce9e (diff) | |
| download | serenity-cdbd878a145c97ffef9ba154071803fdc6c58ac3.zip | |
Kernel: Fix APIC timer calibration to be more accurate
We were calibrating it to 260 instead of 250 ticks per second (being
off by one for the 1/10th second calibration time), resulting in
ticks of only ~3.6 ms instead of ~4ms. This gets us closer to ~4ms,
but because the APIC isn't nearly as precise as e.g. HPET, it will
only be a best effort. Then, use the higher precision reference
timer to more accurately calculate how many ticks we actually get
each second.
Also the frequency calculation was off, causing a "Frequency too slow"
error with VMware.
Fixes some problems observed in #5539
Diffstat (limited to 'Kernel/Time/HPET.h')
| -rw-r--r-- | Kernel/Time/HPET.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/Kernel/Time/HPET.h b/Kernel/Time/HPET.h index 7cdc15fb74..a2d04dd774 100644 --- a/Kernel/Time/HPET.h +++ b/Kernel/Time/HPET.h @@ -46,6 +46,8 @@ public: static HPET& the(); u64 frequency() const { return m_frequency; } + u64 raw_counter_ticks_to_ns(u64) const; + u64 ns_to_raw_counter_ticks(u64) const; const NonnullRefPtrVector<HPETComparator>& comparators() const { return m_comparators; } void disable(const HPETComparator&); @@ -60,6 +62,7 @@ public: void disable_periodic_interrupt(const HPETComparator& comparator); u64 update_time(u64& seconds_since_boot, u32& ticks_this_second, bool query_only); + u64 read_main_counter_unsafe() const; u64 read_main_counter() const; Vector<unsigned> capable_interrupt_numbers(u8 comparator_number); @@ -75,7 +78,7 @@ private: bool is_periodic_capable(u8 comparator_number); void set_comparators_to_optimal_interrupt_state(size_t timers_count); - u64 calculate_ticks_in_nanoseconds() const; + u64 nanoseconds_to_raw_ticks() const; PhysicalAddress find_acpi_hpet_registers_block(); explicit HPET(PhysicalAddress acpi_hpet); |