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Jphillips

Member

Registered: 2019-08-23

Posts: 68

Monitoring DIMM temperatures using i2c-tools and jc42

I'm trying to configure lm_sensors to monitor my RAM, and I understand the basics from the Arch Wiki page, but it doesn't quite give enough explanation for me to figure out how to adapt it to my system. Specifically, for me, the output of i2cdetect is:

$ sudo i2cdetect -l
i2c-0	i2c       	Synopsys DesignWare I2C adapter 	I2C adapter
i2c-1	i2c       	AMDGPU SMU 0                    	I2C adapter
i2c-2	i2c       	AMDGPU SMU 1                    	I2C adapter
i2c-3	i2c       	AMDGPU DM i2c hw bus 0          	I2C adapter
i2c-4	i2c       	AMDGPU DM i2c hw bus 1          	I2C adapter
i2c-5	i2c       	AMDGPU DM i2c hw bus 2          	I2C adapter
i2c-6	i2c       	AMDGPU DM i2c hw bus 3          	I2C adapter
i2c-7	i2c       	AMDGPU DM aux hw bus 0          	I2C adapter
i2c-8	i2c       	AMDGPU DM aux hw bus 1          	I2C adapter
i2c-9	i2c       	AMDGPU DM aux hw bus 2          	I2C adapter
i2c-10	smbus     	SMBus PIIX4 adapter port 0 at 0b00	SMBus adapter
i2c-11	smbus     	SMBus PIIX4 adapter port 2 at 0b00	SMBus adapter
i2c-12	smbus     	SMBus PIIX4 adapter port 1 at 0b20	SMBus adapter

How do I determine which SMBus holds the RAM sticks? Is it the one with "port 0"?

If so, the corresponding devices connected are:

$ sudo i2cdetect -y 10
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- 1c 1d 1e 1f 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: 30 -- -- -- -- 35 36 -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- 54 55 56 57 -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- 71 -- -- -- -- 76 --

According to the wiki, the RAM temperatures start at 0x18 and the SPD's at 0x50 onward. For me, does this mean that the 1c, 1d, 1e, 1f indicate RAM sticks? Or am I misunderstanding this output and/or the previous output?

Thanks!

Last edited by Jphillips (2024-03-06 10:53:40)

Jphillips

Member

Registered: 2019-08-23

Posts: 68

Re: Monitoring DIMM temperatures using i2c-tools and jc42

For those who stumble upon this in the future, it turns out I didn't need to go down this route. Just loading the jc42 module and rerunning lm_sensors allowed the RAM to be detected.