Commit Graph

248 Commits

Author SHA1 Message Date
Alexander Motin
1703f2b424 Rename statclock_disable variable to atrtcclock_disable that it actually is,
and hide it inside of atrtc driver. Add new tunable hint.atrtc.0.clock
controlling it. Setting it to 0 disables using RTC clock as stat-/
profclock sources.

Teach i386 and amd64 SMP platforms to emulate stat-/profclocks using i8254
hardclock, when LAPIC and RTC clocks are disabled.

This allows to reduce global interrupt rate of idle system down to about
100 interrupts per core, permitting C3 and deeper C-states provide maximum
CPU power efficiency.
2009-05-03 17:47:21 +00:00
Alexander Motin
58a2bb4996 Add resume methods to i8254 and atrtc devices. 2009-05-01 21:43:04 +00:00
Poul-Henning Kamp
7e82012aff atrtc.c is a repocopy of the RTC device driver from i386/isa/clock.c
In addition to the device driver functionality, it exposes a number of
functions which various other bits of code use to fondle the RTC chip.
2008-04-14 07:57:15 +00:00
Poul-Henning Kamp
2946435299 Move i386 to generic RTC handling code.
Make clock_if.m and subr_rtc.c standard on i386

Add hints for "atrtc" driver, for non-PnP, non-ACPI systems.
NB: Make sure to install GENERIC.hints into /boot/device.hints in these!

Nuke MD inittodr(), resettodr() functions.

Don't attach to PHP0B00 in the "attimer" dummy driver any more, and remove
comments that no longer apply for that reason.

Add new "atrtc" device driver, which handles IBM PC AT Real Time
Clock compatible devices using subr_rtc and clock_if.

This driver is not entirely clean: other code still fondles the
hardware to get a statclock interrupt on non-ACPI timer systems.

Wrap some overly long lines.

After it has settled in -current, this will be ported to amd64.

Technically this is MFC'able, but I fail to see a good reason.
2008-04-12 20:46:06 +00:00
Poul-Henning Kamp
dad3b6c6fd Back in the good old days, PC's had random pieces of rock for
frequency generation and what frequency the generated was anyones
guess.

In general the 32.768kHz RTC clock x-tal was the best, because that
was a regular wrist-watch Xtal, whereas the X-tal generating the
ISA bus frequency was much lower quality, often costing as much as
several cents a piece, so it made good sense to check the ISA bus
frequency against the RTC clock.

The other relevant property of those machines, is that they
typically had no more than 16MB RAM.

These days, CPU chips croak if their clocks are not tightly within
specs and all necessary frequencies are derived from the master
crystal by means if PLL's.

Considering that it takes on average 1.5 second to calibrate the
frequency of the i8254 counter, that more likely than not, we will
not actually use the result of the calibration, and as the final
clincher, we seldom use the i8254 for anything besides BEL in
syscons anyway, it has become time to drop the calibration code.

If you need to tell the system what frequency your i8254 runs,
you can do so from the loader using hw.i8254.freq or using the
sysctl kern.timecounter.tc.i8254.frequency.
2008-03-26 22:12:00 +00:00
Poul-Henning Kamp
e465985885 The "free-lance" timer in the i8254 is only used for the speaker
these days, so de-generalize the acquire_timer/release_timer api
to just deal with speakers.

The new (optional) MD functions are:
	timer_spkr_acquire()
	timer_spkr_release()
and
	timer_spkr_setfreq()

the last of which configures the timer to generate a tone of a given
frequency, in Hz instead of 1/1193182th of seconds.

Drop entirely timer2 on pc98, it is not used anywhere at all.

Move sysbeep() to kern/tty_cons.c and use the timer_spkr*() if
they exist, and do nothing otherwise.

Remove prototypes and empty acquire-/release-timer() and sysbeep()
functions from the non-beeping archs.

This eliminate the need for the speaker driver to know about
i8254frequency at all.  In theory this makes the speaker driver MI,
contingent on the timer_spkr_*() functions existing but the driver
does not know this yet and still attaches to the ISA bus.

Syscons is more tricky, in one function, sc_tone(), it knows the hz
and things are just fine.

In the other function, sc_bell() it seems to get the period from
the KDMKTONE ioctl in terms if 1/1193182th second, so we hardcode
the 1193182 and leave it at that.  It's probably not important.

Change a few other sysbeep() uses which obviously knew that the
argument was in terms of i8254 frequency, and leave alone those
that look like people thought sysbeep() took frequency in hertz.

This eliminates the knowledge of i8254_freq from all but the actual
clock.c code and the prof_machdep.c on amd64 and i386, where I think
it would be smart to ask for help from the timecounters anyway [TBD].
2008-03-26 20:09:21 +00:00
Poul-Henning Kamp
ebfbcd612a Rename timer0_max_count to i8254_max_count.
Rename timer0_real_max_count to i8254_real_max_count and make it static.
Rename timer_freq to i8254_freq and make it a loader tunable.
2008-03-26 15:03:24 +00:00
Poul-Henning Kamp
f168bfa529 The RTC related pscnt and psdiv variables have no business being public. 2008-03-26 13:25:27 +00:00
John Baldwin
c05655bfda Use cpu_spinwait() (i.e., "pause") when spinning on rdtsc during DELAY().
MFC after:	1 week
2008-01-17 18:59:38 +00:00
Peter Wemm
d556638404 Split /dev/nvram driver out of isa/clock.c for i386 and amd64. I have not
refactored it to be a generic device.
Instead of being part of the standard kernel, there is now a 'nvram' device
for i386/amd64.  It is in DEFAULTS like io and mem, and can be turned off
with 'nodevice nvram'.  This matches the previous behavior when it was
first committed.
2007-10-26 03:23:54 +00:00
David Malone
9be70a793e It seems that some i386 mothermoards either do not implement the
day of week field correctly, or they remember bad values that are
written into the day of week field. For this reason, ignore the day
of week field when reading the clock on i386 rather than bailing if
it is set incorrectly.

Problems were seen on a number of platforms, including VMWare, qemu,
EPIA ME6000, Epox-3PTA and ABIT-SL30T.

This is a slightly different fix to that proposed by Ted in his PR,
but the same basic idea.

PR:		111117
Submitted by:	Ted Faber <faber@lunabase.org>
Approved by:	re (rwatson)
MFC after:	3 weeks
2007-07-27 09:34:42 +00:00
David Malone
6d8617d42a If clock_ct_to_ts fails to convert time time from the real time clock,
print a one line error message. Add some comments on not being able to
trust the day of week field (I'll act on these comments in a follow up
commit).

Approved by:	re
MFC after:	3 weeks
2007-07-23 09:42:32 +00:00
Peter Wemm
5915fb72fb Prototype (but functional) Linux-ish /dev/nvram interface to the extra
114 bytes of cmos ram in the PC clock chip.  The big difference between
this and the Linux version is that we do not recalculate the checksums
for bytes 16..31.

We use this at work when cloning identical machines - we can copy the
bios settings as well.  Reading /dev/nvram gives 114 bytes of data but
you can seek/read/write whichever bytes you like.

Yes, this is a "foot, gun, fire!" type of device.
2007-06-15 22:58:14 +00:00
David Malone
041b706b2f Despite several examples in the kernel, the third argument of
sysctl_handle_int is not sizeof the int type you want to export.
The type must always be an int or an unsigned int.

Remove the instances where a sizeof(variable) is passed to stop
people accidently cut and pasting these examples.

In a few places this was sysctl_handle_int was being used on 64 bit
types, which would truncate the value to be exported.  In these
cases use sysctl_handle_quad to export them and change the format
to Q so that sysctl(1) can still print them.
2007-06-04 18:25:08 +00:00
Bruce Evans
d78180f8f5 Partial fix for a bug in rev.1.231. If suspend/resume clobbers the
RTC state, then it may clobber the RTC index register, so the index
register must be restored before using it to restore control registers
in rtc_restore().

The following problems remain:
- rtc_restore() is only called if pmtimer is configured.  Buggy
  suspend/resumes are more likely to clobber the index register than
  a control register, so pmtimer is more needed than it used to be.
- pmtimer doesn't exist for amd64.
- Restoring of the RTC state may race with rtcintr().  If an RTC
  interrupt is handled before the state is restored, then rtcin(RTC_INTR)
  in rtcintr() may read from the wrong register, so rtcintr() may spin
  forever.  This may be mitigated by the most common state clobbering
  being to turn off RTC interrupts.
2007-03-05 09:10:17 +00:00
Yoshihiro Takahashi
de038d5ffc style(9). 2007-03-04 04:55:19 +00:00
Paolo Pisati
ef544f6312 o break newbus api: add a new argument of type driver_filter_t to
bus_setup_intr()

o add an int return code to all fast handlers

o retire INTR_FAST/IH_FAST

For more info: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=465712+0+current/freebsd-current

Reviewed by: many
Approved by: re@
2007-02-23 12:19:07 +00:00
Bruce Evans
71799af2d5 Cleaned up declaration and initialization of clock_lock. It is only
used by clock code, so don't export it to the world for machdep.c to
initialize.  There is a minor problem initializing it before it is
used, since although clock initialization is split up so that parts
of it can be done early, the first part was never done early enough
to actually work.  Split it up a bit more and do the first part as
late as possible to document the necessary order.  The functions that
implement the split are still bogusly exported.

Cleaned up initialization of the i8254 clock hardware using the new
split.  Actually initialize it early enough, and don't work around it
not being initialized in DELAY() when DELAY() is called early for
initialization of some console drivers.

This unfortunately moves a little more code before the early debugger
breakpoint so that it is harder to debug.  The ordering of console and
related initialization is delicate because we want to do as little as
possible before the breakpoint, but must initialize a console.
2007-01-23 08:01:20 +00:00
Bruce Evans
b73057227b Optimized RTC accesses by avoiding null writes to the index register
and by only delaying when an RTC register is written to.  The delay
after writing to the data register is now not just a workaround.

This reduces the number of ISA accesses in the usual case from 4 to
1.  The usual case is 2 rtcin()'s for each RTC interrupt.  The index
register is almost always RTC_INTR for this.  The 3 extra ISA accesses
were 1 for writing the index and 2 for delays.  Some delays are needed
in theory, but in practice they now just slow down slow accesses some
more since almost eveyone including us does them wrong so modern systems
enforce sufficient delays in hardware.  I used to have the delays ifdefed
out, but with the index register optimization the delays are rarely
executed so the old magic ones can be kept or even implemented non-
magically without significant cost.

Optimizing RTC interrupt handling is more interesting than it used to
be because RTC interrupts are currently needed to fix the more efficient
apic timer interrupts on some systems.  apic_timer_hz is normally 2000
so the RTC interrupt rate needs to be 2048 to keep the apic timer
firing on such systems.  Without these changes, each RTC interrupt
normally took 10 ISA accesses (2 PIC accesses and 2 sets of 4 RTC
accesses).  Each ISA access takes 1-1.5uS so 10 of then at 2048 Hz
takes 2-3% of a CPU.  Now 4 of them take 0.8-1.2% of a CPU.
2006-12-03 03:49:28 +00:00
Poul-Henning Kamp
e4c9547050 Use calendaric calculation support from subr_clock.c instead of home-rolled.
Eventually, this RTC should probably use subr_rtc.c as well
2006-10-02 16:18:40 +00:00
Poul-Henning Kamp
b69f71eb29 Second part of a little cleanup in the calendar/timezone/RTC handling.
Split subr_clock.c in two parts (by repo-copy):
   subr_clock.c contains generic RTC and calendaric stuff. etc.
   subr_rtc.c contains the newbus'ified RTC interface.

Centralize the machdep.{adjkerntz,disable_rtc_set,wall_cmos_clock}
sysctls and associated variables into subr_clock.c.  They are
not machine dependent and we have generic code that relies on being
present so they are not even optional.
2006-10-02 15:42:02 +00:00
Poul-Henning Kamp
f645b0b51c First part of a little cleanup in the calendar/timezone/RTC handling.
Move relevant variables to <sys/clock.h> and fix #includes as necessary.

Use libkern's much more time- & spamce-efficient BCD routines.
2006-10-02 12:59:59 +00:00
Warner Losh
ddebcb409b Eliminate one set of XBOX #ifdefs. The Xbox code just needs to set a
different TIMER_FREQ value than default.  Accomplish this via the
config file rather than via an #ifdef.
2006-08-09 23:47:38 +00:00
John Baldwin
b439e431bf Tweak how the MD code calls the fooclock() methods some. Instead of
passing a pointer to an opaque clockframe structure and requiring the
MD code to supply CLKF_FOO() macros to extract needed values out of the
opaque structure, just pass the needed values directly.  In practice this
means passing the pair (usermode, pc) to hardclock() and profclock() and
passing the boolean (usermode) to hardclock_cpu() and hardclock_process().
Other details:
- Axe clockframe and CLKF_FOO() macros on all architectures.  Basically,
  all the archs were taking a trapframe and converting it into a clockframe
  one way or another.  Now they can just extract the PC and usermode values
  directly out of the trapframe and pass it to fooclock().
- Renamed hardclock_process() to hardclock_cpu() as the latter is more
  accurate.
- On Alpha, we now run profclock() at hz (profhz == hz) rather than at
  the slower stathz.
- On Alpha, for the TurboLaser machines that don't have an 8254
  timecounter, call hardclock() directly.  This removes an extra
  conditional check from every clock interrupt on Alpha on the BSP.
  There is probably room for even further pruning here by changing Alpha
  to use the simplified timecounter we use on x86 with the lapic timer
  since we don't get interrupts from the 8254 on Alpha anyway.
- On x86, clkintr() shouldn't ever be called now unless using_lapic_timer
  is false, so add a KASSERT() to that affect and remove a condition
  to slightly optimize the non-lapic case.
- Change prototypeof  arm_handler_execute() so that it's first arg is a
  trapframe pointer rather than a void pointer for clarity.
- Use KCOUNT macro in profclock() to lookup the kernel profiling bucket.

Tested on:	alpha, amd64, arm, i386, ia64, sparc64
Reviewed by:	bde (mostly)
2005-12-22 22:16:09 +00:00
Peter Wemm
737429bc96 MFamd64 rev 1.223: Use the TSC to implement DELAY() if not marked broken
and it has been calibrated.
2005-12-13 19:08:55 +00:00
Warner Losh
51ef421d92 Add support for XBOX to the FreeBSD port. The xbox architecture is
nearly identical to wintel/ia32, with a couple of tweaks.  Since it is
so similar to ia32, it is optionally added to a i386 kernel.  This
port is preliminary, but seems to work well.  Further improvements
will improve the interaction with syscons(4), port Linux nforce driver
and future versions of the xbox.

This supports the 64MB and 128MB boxes.  You'll need the most recent
CVS version of Cromwell (the Linux BIOS for the XBOX) to boot.

Rink will be maintaining this port, and is interested in feedback.
He's setup a website http://xbox-bsd.nl to report the latest
developments.

Any silly mistakes are my fault.

Submitted by: Rink P.W. Springer rink at stack dot nl and
	Ed Schouten ed at fxq dot nl
2005-11-09 03:55:40 +00:00
John Baldwin
db015a9153 Fixup some more fallout from the lapic/i8254 changes:
- Make sure timer0_max_count is set to a correct value in the lapic case.
- Revert i8254_restore() to explicitly reprogram timer 0 rather than
  calling set_timer_freq() to do it.  set_timer_freq() only reprograms
  the counter if the max count changes which it never does on resume.  This
  unbreaks suspend/resume for several people.

Tested by:	marks, others
Reviewed by:	bde
MFC after:	3 days
2005-07-13 15:43:21 +00:00
John Baldwin
623b1a868e Remove a || 1 that crept into the i8254 commit and was subsequently
copied and pasted.  I had actually tested without this change in my
trees as had the other testers.

Reported by:	bde, Rostislav Krasny rosti dot bsd at gmail dot com
Approved by:	re (scottl)
Pointy hat to:	jhb
2005-07-05 20:13:12 +00:00
John Baldwin
7df0015945 Use a simpler implementation for the i8254 timecounter when using the lapic
timer since irq0 isn't being driven at hz in that case and we don't need to
try to handle edge cases with rollover, etc. that require irq0 to be firing
for the timecounter to actually work.

Submitted by:	phk
Tested by:	schweikh
Approved by:	re (scottl)
2005-07-01 15:47:27 +00:00
Yoshihiro Takahashi
24072ca35b - Move timerreg.h to <arch>/include and split i8253 specific defines into
i8253reg.h, and add some defines to control a speaker.
- Move PPI related defines from i386/isa/spkr.c into ppireg.h and use them.
- Move IO_{PPI,TIMER} defines into ppireg.h and timerreg.h respectively.
- Use isa/isareg.h rather than <arch>/isa/isa.h.

Tested on: i386, pc98
2005-05-14 09:10:02 +00:00
Matthew N. Dodd
93fa9a8d72 Replace spl protection in rtcin() and writertc() with spinlocks
using the existing clock_lock mutex.
2005-04-12 20:49:31 +00:00
John Baldwin
d336ab43c6 - Don't enable periodic interrupts from the RTC by default in rtc_statusb.
Instead, explicitly enable them when we setup the interrupt handler.
  Also, move the setting of stathz and profhz down to the same place so
  that the code flow is simpler and easier to follow.
- Don't setup an interrupt handler for IRQ0 if we are using the lapic timer
  as it doesn't do anything productive in that case.
2005-03-24 21:34:16 +00:00
Peter Wemm
0cd202bb09 Whitespace sync with amd64. (Rather than re-add the extra blank lines
on amd64, I'm removing them here)
2005-03-11 22:10:25 +00:00
John Baldwin
dd1d2889f2 - Remove the BURN_BRIDGES marked support for hooking into the ISA timer 0
interrupt.
- Remove the timer_func variable as it now has a static value of
  hardclock() and is only used in one place.

Axe borrowed from:	phk
2005-03-09 15:33:58 +00:00
John Baldwin
e8ce55117b Use the local APIC timer to drive the various kernel clocks on SMP machines
rather than forwarding interrupts from the clock devices around using IPIs:
- Add an IDT vector that pushes a clock frame and calls
  lapic_handle_timer().
- Add functions to program the local APIC timer including setting the
  divisor, and setting up the timer to either down a periodic countdown
  or one-shot countdown.
- Add a lapic_setup_clock() function that the BSP calls from
  cpu_init_clocks() to setup the local APIC timer if it is going to be
  used.  The setup uses a one-shot countdown to calibrate the timer.  We
  then program the timer on each CPU to fire at a frequency of hz * 3.
  stathz is defined as freq / 23 (hz * 3 / 23), and profhz is defined as
  freq / 2 (hz * 3 / 2).  This gives the clocks relatively prime divisors
  while keeping a low LCM for the frequency of the clock interrupts.
  Thanks to Peter Jeremy for suggesting this approach.
- Remove the hardclock and statclock forwarding code including the two
  associated IPIs.  The bitmap IPI handler has now effectively degenerated
  to just IPI_AST.
- When the local APIC timer is used we don't turn the RTC on at all, but
  we still enable interrupts on the ISA timer 0 (i8254) for timecounting
  purposes.
2005-02-08 20:25:07 +00:00
John Baldwin
aa96fcdb61 Anytime we write to the RTC's status B register to possibly enable
interrupts, read from the interrupt status register to clear any pending
interrupts.  Otherwise in some rare cases the RTC would never fire any
interrupts as it constantly thinks it has an interrupt pending.

PR:		i386/17800
PR:		kern/76776
Submitted by:	Jose M. Alcaide jose at we dot lc dot ehu dot es
MFC after:	2 weeks
2005-02-03 19:06:03 +00:00
Marcel Moolenaar
45cfc0a914 Partially revert previous commit. Calling getit() unconditionally fixed
a problem that could also be fixed differently without reverting previous
attempts to fix DELAY while the debugger is active (rev 1.204). The bug
was that the i8254 implements a countdown timer, while for (k)db_active
a countup timer was implemented. This resulted in premature termination
and consequently the breakage of DELAY. The fix (relative to rev 1.211)
is to implement a countdown timer for the kdb_active case. As such the
ability to step clock initialization is preserved and DELAY does what is
expected of it.

Blushed: bde :-)
Submitted by: bde
2004-07-11 17:50:59 +00:00
Marcel Moolenaar
7f46949fdf Call getit() unconditionally and only grab clock_lock when the
debugger is not active. The fixes breakages of DELAY() when
running in the debugger, because not calling getit() when the
debugger is active yields a DELAY that doesn't.
2004-07-10 22:16:18 +00:00
Poul-Henning Kamp
41ee9f1c69 Add some missing <sys/module.h> includes which are masked by the
one on death-row in <sys/kernel.h>
2004-05-30 17:57:46 +00:00
John Baldwin
d4d4ece72d Trim unused includes. 2004-05-11 20:14:53 +00:00
John Baldwin
f9acc6410e - The i8254 uses IRQ 0, not IRQ 8. Correct i8254_intsrc to reference the
correct interrupt source.
- Cache a pointer to the i8254_intsrc's pending method to avoid several
  pointer indirections in i8254_get_timecount().

Reported by:	bde
2004-04-27 20:03:26 +00:00
Warner Losh
f36cfd49ad Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson
2004-04-07 20:46:16 +00:00
Poul-Henning Kamp
daf9092bcd Don't disable the TSC with statclock_disable. 2003-11-13 10:02:12 +00:00
John Baldwin
6f92bdd0c1 New APIC support code:
- The apic interrupt entry points have been rewritten so that each entry
  point can serve 32 different vectors.  When the entry is executed, it
  uses one of the 32-bit ISR registers to determine which vector in its
  assigned range was triggered.  Thus, the apic code can support 159
  different interrupt vectors with only 5 entry points.
- We now always to disable the local APIC to work around an errata in
  certain PPros and then re-enable it again if we decide to use the APICs
  to route interrupts.
- We no longer map IO APICs or local APICs using special page table
  entries.  Instead, we just use pmap_mapdev().  We also no longer
  export the virtual address of the local APIC as a global symbol to
  the rest of the system, but only in local_apic.c.  To aid this, the
  APIC ID of each CPU is exported as a per-CPU variable.
- Interrupt sources are provided for each intpin on each IO APIC.
  Currently, each source is given a unique interrupt vector meaning that
  PCI interrupts are not shared on most machines with an I/O APIC.
  That mapping for interrupt sources to interrupt vectors is up to the
  APIC enumerator driver however.
- We no longer probe to see if we need to use mixed mode to route IRQ 0,
  instead we always use mixed mode to route IRQ 0 for now.  This can be
  disabled via the 'NO_MIXED_MODE' kernel option.
- The npx(4) driver now always probes to see if a built-in FPU is present
  since this test can now be performed with the new APIC code.  However,
  an SMP kernel will panic if there is more than one CPU and a built-in
  FPU is not found.
- PCI interrupts are now properly routed when using APICs to route
  interrupts, so remove the hack to psuedo-route interrupts when the
  intpin register was read.
- The apic.h header was moved to apicreg.h and a new apicvar.h header
  that declares the APIs used by the new APIC code was added.
2003-11-03 21:53:38 +00:00
Warner Losh
00dc18b5a8 Per TRB vote: restore the aquire_timer0 and associated goo. This will
be gone in FreeBSD 6, so put BURN_BRIDGES around it.  The TRB also
felt that if something better comes along sooner, it can be used to
replace this code.

Delayed by: BSDcon and subsequent disk crash.
2003-09-24 15:33:33 +00:00
Bruce Evans
4df0520624 clock.c:
Quick fix for calling DELAY() for ddb input in some (atkbd-based)
console drivers.  ddb must not use any normal locks, but DELAY()
normally calls getit() which needs clock_lock.  One problem with using
normal locks in ddb is that deadlock is possible, but deadlock on
clock_lock is unlikely becaluse clock_lock is bogusly recursive,
apparently just to hide the problem of ddb using it.  The i8254 clock
hardware has mostly write-only registers so it is important for it to
use a lock that gives exclusive access.  (atkbd hardware is also
unfriendly to reentrant software but that problem is more local and
already solved.)  I mostly saw the symptoms of the bug caused by
unlocking in getit() running cpu_unpend().  cpu_unpend() should not
be called while in ddb and Debugger() calls for failing assertions
about this caused a breakpoint within ddb.

ddb must also not call getit() because ddb may be being used to step
through clock initialization code that has stopped or otherwise mangled
the clock.  If the clock is stopped, then getit() always returns the
same value and DELAY() takes forever if it trusts getit().

The quick fix is implement DELAY(n) as (n * timer_freq / 1000000)
inb(0x84)'s if ddb is active.

machdep.c:
Don't permit recursion on clock_lock.
2003-09-07 14:23:08 +00:00
Poul-Henning Kamp
78a49a45bc Give timecounters a numeric quality field.
A timecounter will be selected when registered if its quality is
not negative and no less than the current timecounters.

Add a sysctl to report all available timecounters and their qualities.

Give the dummy timecounter a solid negative quality of minus a million.

Give the i8254 zero and the ACPI 1000.

The TSC gets 800, unless APM or SMP forces it negative.

Other timecounters default to zero quality and thereby retain current
selection behaviour.
2003-08-16 08:23:53 +00:00
Poul-Henning Kamp
8dcee923b5 remove acquire_timer0() and release_timer0() and related stuff. 2003-08-15 15:50:49 +00:00
Poul-Henning Kamp
2fbc275447 Dont initialize a TSC timecounter until we know if it is broken or not. 2003-08-06 15:05:27 +00:00
David E. O'Brien
006124d811 Use __FBSDID(). 2003-06-02 16:32:55 +00:00