Date: Thu, 5 May 2005 13:13:33 +0200 From: Anthony Atkielski <atkielski.anthony@wanadoo.fr> To: freebsd-questions@freebsd.org Subject: Re: Clock running fast Message-ID: <995071073.20050505131333@wanadoo.fr> In-Reply-To: <LOBBIFDAGNMAMLGJJCKNOEENFBAA.tedm@toybox.placo.com> References: <352039115.20050505104330@wanadoo.fr> <LOBBIFDAGNMAMLGJJCKNOEENFBAA.tedm@toybox.placo.com>
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Ted Mittelstaedt writes: > Anthony, you really need to look in the code sometime: It takes a very long time to find relevant sections of code, and unless the author was very conscientious, there are usually few or no explanatory comments, anyway. > /usr/src/sys/dev/acpica/acpi_timer.c Thanks. > * If all tests of the counter succeed, use the ACPI-fast method. If > * at least one failed, default to using the safe routine, which reads > * the timer multiple times to get a consistent value before returning. Whatever that means. > /usr/src/sys/i386/isa/clock.c > /usr/src/sys/i386/i386/tsc.c Thanks > /* > * We can not use the TSC if we support APM. Precise timekeeping > * on an APM'ed machine is at best a fools pursuit, since > * any and all of the time spent in various SMM code can't > * be reliably accounted for. Reading the RTC is your only > * source of reliable time info. The i8254 looses too of course > * but we need to have some kind of time... > * We don't know at this point whether APM is going to be used > * or not, nor when it might be activated. Play it safe. > */ Hmm. I think APM is turned off on my machine, at least that's what FreeBSD says. The manual for the MB doesn't say anything about SMI use. I don't like the idea of a motherboard stealing cycles from my machine; it sounds way too much like a virus, and a virus built into the hardware is the worst nightmare. -- Anthony
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