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Date:      Sat, 03 Apr 2010 16:54:52 +0100
From:      Bartosz Fabianowski <freebsd@chillt.de>
To:        "Alexandre \"Sunny\" Kovalenko" <gaijin.k@ovi.com>
Cc:        freebsd-acpi@freebsd.org, Ian Smith <smithi@nimnet.asn.au>
Subject:   Re: Spurious thermal shutdowns on Dell Studio 1557
Message-ID:  <4BB764CC.60500@chillt.de>
In-Reply-To: <1270308642.1455.10.camel@RabbitsDen>
References:  <4BB69279.6060005@chillt.de>	 <20100403152134.V35463@sola.nimnet.asn.au> <4BB74BC4.9070409@chillt.de>	 <20100404012906.I35463@sola.nimnet.asn.au> <1270308642.1455.10.camel@RabbitsDen>

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> I would not override _CRT

Intel seem not to have documented the maximal operating temperature for
this CPU (Core i7 Q720M). But overclocking enthusiast forums mention
automatic throttling from 100°C onward. So while I cannot be sure, I
think the CPU should survive just fine with a _CRT of more than 85°C.

> Something to the tune of:
>
> hw.acpi.thermal.tz0.passive_cooling=1 hw.acpi.thermal.user_override=1
> hw.acpi.thermal.tz0._PSV=75C

I can do that. But since the CPU is running at ~60°C when completely
idle, this will essentially force throttling whenever I do anything that
demands a bit of CPU. I bought a quad-core i7 specifically because I 
want CPU power. Forcing the CPU to throttle all the time would remove 
any advantage of having bought such an expensive CPU.

> * Is tz0 the only thermal zone you have on this machine?

All of this is TZ1. TZ0 does exist as well but reports a constant 26.8°C
with a _CRT of 127.0°C - not very interesting.

> * Are you using 'powerd' and, if so, what are the settings?

Yes, powerd is running with default settings. I can see dev.cpu.0.freq 
going up and down so powerd seems to be working.

> * What does 'sysctl dev.cpu' say?

As the output is rather long, I put it at the end of this e-mail.

> Perennial favorite is to pry off the heatsink, clean and re-apply the
> grease in moderation.

I am very reluctant to do this. The laptop is barely three months old. 
As long as it is still under warranty, I really do not want to take it 
apart. Also, shaving off 3-4°C will not cut it anyway. To prevent the 
spurious shutdowns without overriding _CRT, I would need the CPU to run 
at least 10-15°C cooler.

- Bartosz

Output of sysctl dev.cpu:

dev.cpu.0.%desc: ACPI CPU
dev.cpu.0.%driver: cpu
dev.cpu.0.%location: handle=\_PR_.CPU0
dev.cpu.0.%pnpinfo: _HID=none _UID=0
dev.cpu.0.%parent: acpi0
dev.cpu.0.temperature: 55.0C
dev.cpu.0.freq: 1463
dev.cpu.0.freq_levels: 1597/35000 1463/31000 1330/27000 1197/23000 
1064/19000 931/15000 814/13125 698/11250 581/9375 465/7500 349/5625 
232/3750 116/1875
dev.cpu.0.cx_supported: C1/3
dev.cpu.0.cx_lowest: C1
dev.cpu.0.cx_usage: 100.00% last 500us
dev.cpu.1.%desc: ACPI CPU
dev.cpu.1.%driver: cpu
dev.cpu.1.%location: handle=\_PR_.CPU1
dev.cpu.1.%pnpinfo: _HID=none _UID=0
dev.cpu.1.%parent: acpi0
dev.cpu.1.temperature: 56.0C
dev.cpu.1.cx_supported: C1/3
dev.cpu.1.cx_lowest: C1
dev.cpu.1.cx_usage: 100.00% last 500us
dev.cpu.2.%desc: ACPI CPU
dev.cpu.2.%driver: cpu
dev.cpu.2.%location: handle=\_PR_.CPU2
dev.cpu.2.%pnpinfo: _HID=none _UID=0
dev.cpu.2.%parent: acpi0
dev.cpu.2.temperature: 54.0C
dev.cpu.2.cx_supported: C1/3
dev.cpu.2.cx_lowest: C1
dev.cpu.2.cx_usage: 100.00% last 500us
dev.cpu.3.%desc: ACPI CPU
dev.cpu.3.%driver: cpu
dev.cpu.3.%location: handle=\_PR_.CPU3
dev.cpu.3.%pnpinfo: _HID=none _UID=0
dev.cpu.3.%parent: acpi0
dev.cpu.3.temperature: 54.0C
dev.cpu.3.cx_supported: C1/3
dev.cpu.3.cx_lowest: C1
dev.cpu.3.cx_usage: 100.00% last 500us
dev.cpu.4.%desc: ACPI CPU
dev.cpu.4.%driver: cpu
dev.cpu.4.%location: handle=\_PR_.CPU4
dev.cpu.4.%pnpinfo: _HID=none _UID=0
dev.cpu.4.%parent: acpi0
dev.cpu.4.temperature: 56.0C
dev.cpu.4.cx_supported: C1/3
dev.cpu.4.cx_lowest: C1
dev.cpu.4.cx_usage: 100.00% last 500us
dev.cpu.5.%desc: ACPI CPU
dev.cpu.5.%driver: cpu
dev.cpu.5.%location: handle=\_PR_.CPU5
dev.cpu.5.%pnpinfo: _HID=none _UID=0
dev.cpu.5.%parent: acpi0
dev.cpu.5.temperature: 56.0C
dev.cpu.5.cx_supported: C1/3
dev.cpu.5.cx_lowest: C1
dev.cpu.5.cx_usage: 100.00% last 500us
dev.cpu.6.%desc: ACPI CPU
dev.cpu.6.%driver: cpu
dev.cpu.6.%location: handle=\_PR_.CPU6
dev.cpu.6.%pnpinfo: _HID=none _UID=0
dev.cpu.6.%parent: acpi0
dev.cpu.6.temperature: 54.0C
dev.cpu.6.cx_supported: C1/3
dev.cpu.6.cx_lowest: C1
dev.cpu.6.cx_usage: 100.00% last 500us
dev.cpu.7.%desc: ACPI CPU
dev.cpu.7.%driver: cpu
dev.cpu.7.%location: handle=\_PR_.CPU7
dev.cpu.7.%pnpinfo: _HID=none _UID=0
dev.cpu.7.%parent: acpi0
dev.cpu.7.temperature: 54.0C
dev.cpu.7.cx_supported: C1/3
dev.cpu.7.cx_lowest: C1
dev.cpu.7.cx_usage: 100.00% last 500us



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