Date: Sun, 03 Jul 2005 00:37:04 -0000 From: Maxim Sobolev <sobomax@portaone.com> To: Nate Lawson <nate@root.org> Cc: acpi@FreeBSD.ORG, current@FreeBSD.ORG Subject: Re: patch: p4tcc and speedstep cpufreq drivers Message-ID: <421E49D9.60803@portaone.com> In-Reply-To: <421E42F2.6010105@root.org> References: <20050224011924.992A65D07@ptavv.es.net> <421DA0B5.4060705@portaone.com> <421E42F2.6010105@root.org>
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Nate Lawson wrote: > Maxim Sobolev wrote: > >> Kevin Oberman wrote: >> >>> No joy. I set it to 262 and it was fine. The next step killed the system >>> again. >>> >>> I'm also concerned that taking TCC out of automatic mode might not be a >>> great idea, at least until things like _PSV are supported. When I do a >>> buildkernel, buildworld or any big compile job, I need to slow down the >>> CPU to keep the CPU form frying. It quickly jumps to 185 F. or higher if >>> I don't. If I understand automatic TCC, it should throttle the CPU all >>> by itself to prevent this. >> >> >> >> Taking TCC out of automatic mode doesn't disable thermal controlling >> circuitry completely, so that if the processor overheats it will shut >> down the machine anyway: >> >> --- >> Regardless of enabling of the automatic >> or On-Demand modes, in the event of a catastrophic cooling failure, >> the processor will >> automatically shut down when the silicon has reached a temperature of >> approximately >> 135 °C. At this point the system bus signal THERMTRIP# will go active >> and stay active >> until RESET# has been initiated. --- > > > Correct. Even more so, automatic mode continues to override On-Demand > mode if there is a more moderate thermal condition than THERMTRIP#: > > "On-Demand mode may be used at the same time Automatic mode is enabled, > however, if the system tries to enable the TCC via On-Demand mode at the > same time automatic mode is enabled AND a high temperature condition > exists, the duty cycle of the automatic mode will override the duty > cycle selected by the On-Demand mode." > > Since automatic mode is set by the BIOS before we even boot, things > should be fine. Well, this is quite tricky part of the spec. My reading is that the paragraph above applies only to situation if you are trying to set on-demand mode when both automatic mode is in effect *and* high temperature condition already exists, in that case automatic mode will win and override any manual settings. However, in the case when you have on-demand mode already on and high temperature condition emerges it will have no effect on duty cycle until THERMTRIP# kicks in. That's in my view explains why there is big AND in the text above. -Maxim _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"
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