[coreboot] ASRock E350M1: How to set RAM voltages under coreboot?

Rudolf Marek r.marek at assembler.cz
Sat Apr 20 12:50:08 CEST 2013


For F2A85-M I did that via config option. I think best would be to use similar 
approach as you noted.

How to find out? I would say best approach so far is to monitor changes on GPIO 
or I2C devices.

I did this on asrock board I think. I wrote some script which dumped all GPIO 
settings in hex from SB and superIO.

Then i changed value in bios and compared what GPIO has been changed.


Here is how it is working.

On F2A85-M it was not-so-easy. No GPIO was ever changed and it drove me crazy. 
It turned out that the answer was that there is a device on I2C bus which 
controls this. But beware, modern AMD chipsets usualy have more than 1 i2c bus 
and not all is supported in linux driver. In my case I had to modify the linux 
driver so I could see the bus and the I used i2cdump to dump the device.

Good approach is to use also some overclocking utils for windows, if you are 
lucky some of them contain *.ini files where is written for example GP50 for 
this and that.


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