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flameman
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Joined: 10 Apr 2011
Posts: 39

PostPosted: Tue Apr 26, 2011 5:14 pm    Post subject: apple ppc745x core temperature Reply with quote

reading http://en.gentoo-wiki.com/wiki/Apple_Power_Mac_G4_Quicksilver_%28M8493%29

i ve found this

Quote:

Processor

The PowerPC 7450/7455 processor does not support frequency scaling, so there is no need to activate this feature. Additionally all stock processors don't feature temperature sensors, but it may well be that third party upgrades do.



wandering what does it means .... "additionally all stock processors don't feature temperature sensors, but it may well be that third party upgrades do" ??

"but it may well be that third party upgrades do" ???? isn't there a way in the kernel to read the core temperature ?

Thermal Management Support should do exactly this !

and in the kernel 2.6.32 from gentoo-cd-2010 it should happen that you read this printk (see dmesg)
CPU-temp: 55.0 C, Case: 37.1 C, Fan: 0 (tuned -5)
CPU-temp: 54.7 C, Case: 36.2 C, Fan: 0 (tuned +0)


Quote:

192 config TAU
193 bool "On-chip CPU temperature sensor support"
194 depends on 6xx
195 help
196 G3 and G4 processors have an on-chip temperature sensor called the
197 'Thermal Assist Unit (TAU)', which, in theory, can measure the on-die
198 temperature within 2-4 degrees Celsius. This option shows the current
199 on-die temperature in /proc/cpuinfo if the cpu supports it.
200
201 Unfortunately, on some chip revisions, this sensor is very inaccurate
202 and in many cases, does not work at all, so don't assume the cpu
203 temp is actually what /proc/cpuinfo says it is.




about kernel 2.6.32 ... /proc/cpuinfo is not reporting the core temp

so anybody know a pretty way to get the core temp value for the userland (or a patch/hack/some kind of voodoo magic ) ?



regards
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flameman
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Joined: 10 Apr 2011
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PostPosted: Tue Apr 26, 2011 5:32 pm    Post subject: Re: apple ppc745x core temperature Reply with quote

flameman wrote:

and in the kernel 2.6.32 from gentoo-cd-2010 it should happen that you read this printk (see dmesg)
CPU-temp: 55.0 C, Case: 37.1 C, Fan: 0 (tuned -5)
CPU-temp: 54.7 C, Case: 36.2 C, Fan: 0 (tuned +0)



it is done by

drivers/macintosh/therm_windtunnel.c: print_temp("CPU-temp: ", x.temp );
drivers/macintosh/therm_windtunnel.c: print_temp("CPU-temp: ", temp );


Quote:

*
* The G4 "windtunnel" has a single fan controlled by an
* ADM1030 fan controller and a DS1775 thermostat.
*
* The fan controller is equipped with a temperature sensor
* which measures the case temperature. The DS1775 sensor
* measures the CPU temperature. This driver tunes the
* behavior of the fan. It is based upon empirical observations
* of the 'AppleFan' driver under Mac OS X.
*
* WARNING: This driver has only been testen on Apple's
* 1.25 MHz Dual G4 (March 03). It is tuned for a CPU
* temperature around 57 C.
*

Quote:

MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
MODULE_LICENSE("GPL");


DS1775 thermostat http://www.maxim-ic.com/datasheet/index.mvp/id/2774 (i2c bus device)

Quote:

* Tiny 5-pin SOT-23 package
* ±2°C accuracy from -10°C to +85°C
* Measures temperatures from -55°C to +125°C (-67°F to +257°F)
* 9- to 12-bit user-configurable resolution
* Dedicated thermostatic logic output
* Thermostatic settings are user-programmable
* Data is transferred over 2-wire/SMBus interface
* Eight address versions allow up to eight DS1775 to operate on one bus
* Functionally compatible with the DS75 and LM75
* 2.7V to 5.5V supply range
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