svn commit: r209371 - in head/sys: amd64/amd64 amd64/include conf dev/acpica i386/i386 i386/include isa kern pc98/cbus sys x86/isa x86/x86

[Pawel Worach]

On Jun 21, 2010, at 21:58, Kostik Belousov wrote:

> On Sun, Jun 20, 2010 at 09:33:29PM +0000, Alexander Motin wrote:
>> Author: mav
>> Date: Sun Jun 20 21:33:29 2010
>> New Revision: 209371
>> URL: http://svn.freebsd.org/changeset/base/209371
>> 
>> Log:
>>  Implement new event timers infrastructure. It provides unified APIs for
>>  writing event timer drivers, for choosing best possible drivers by machine
>>  independent code and for operating them to supply kernel with hardclock(),
>>  statclock() and profclock() events in unified fashion on various hardware.
>> 
>>  Infrastructure provides support for both per-CPU (independent for every CPU
>>  core) and global timers in periodic and one-shot modes. MI management code
>>  at this moment uses only periodic mode, but one-shot mode use planned for
>>  later, as part of tickless kernel project.
>> 
>>  For this moment infrastructure used on i386 and amd64 architectures. Other
>>  archs are welcome to follow, while their current operation should not be
>>  affected.
>> 
>>  This patch updates existing drivers (i8254, RTC and LAPIC) for the new
>>  order, and adds event timers support into the HPET driver. These drivers
>>  have different capabilities:
>>   LAPIC - per-CPU timer, supports periodic and one-shot operation, may
>>  freeze in C3 state, calibrated on first use, so may be not exactly precise.
>>   HPET - depending on hardware can work as per-CPU or global, supports
>>  periodic and one-shot operation, usually provides several event timers.
>>   i8254 - global, limited to periodic mode, because same hardware used also
>>  as time counter.
>>   RTC - global, supports only periodic mode, set of frequencies in Hz
>>  limited by powers of 2.
>> 
>>  Depending on hardware capabilities, drivers preferred in following orders,
>>  either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC.
>>  User may explicitly specify wanted timers via loader tunables or sysctls:
>>  kern.eventtimer.timer1 and kern.eventtimer.timer2.
>>  If requested driver is unavailable or unoperational, system will try to
>>  replace it. If no more timers available or "NONE" specified for second,
>>  system will operate using only one timer, multiplying it's frequency by few
>>  times and uing respective dividers to honor hz, stathz and profhz values,
>>  set during initial setup.
> 
> This broke QEMU for me. I cannot boot FreeBSD guest under QEMU anymore.
> QEMU (not FreeBSD kernel) panics with
> qemu: level-triggered hpet not supported
> message.
> 
> Setting kern.eventtimer.timer1 to LAPIC or i8254, and timer2 to NONE
> does not help.

ps. level-triggered hpet is implemented in QEMU git.

-- 
Pawel