Understand why decode-dimms sometimes doesn't detect anything

[lvps]

Some RAMs are not supported and that's it, but this article suggests that after loading some modules related to SMBus the program may work: https://www.richud.com/wiki/Ubuntu_See_Live_RAM_Timings_Decode_DIMMS

Unless it means the usual at24 and eeprom modules, which we are already loading.

Also, why did it break completely on Arch and doesn't detect anything anymore, while 6 months ago it worked?

[lvps]

Current output on arch:

# decode-dimms version $Revision$

Memory Serial Presence Detect Decoder
By Philip Edelbrock, Christian Zuckschwerdt, Burkart Lingner,
Jean Delvare, Trent Piepho and others


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0050
Guessing DIMM is in                              bank 1

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0051
Guessing DIMM is in                              bank 2

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0052
Guessing DIMM is in                              bank 3

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0053
Guessing DIMM is in                              bank 4

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0054
Guessing DIMM is in                              bank 5

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0055
Guessing DIMM is in                              bank 6

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0056
Guessing DIMM is in                              bank 7

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined


Decoding EEPROM: /sys/bus/i2c/drivers/eeprom/13-0057
Guessing DIMM is in                              bank 8

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62                    OK (0x00)
SPD Revision                                     Invalid
Fundamental Memory type                          Unknown (0x00)

---=== Manufacturing Information ===---
Manufacturer                                     Undefined
Part Number                                      Undefined

Same computer, decode-dimms worked in 2018 and detected absolutely nothing in 2019. Now it's detecting something that has the correct checksum and nothing else. Great.

[lvps]

decode-dimms is now recommending the ee1004 module, too

[lvps]

Also test this alternative: https://www.phoronix.com/news/Linux-DIMM-Details-As-Root

[reporter123]

seems at least for the ee1004 module you have some additional steps needed to actually tell the driver where the spds are. https://hackaday.com/2023/04/18/linux-fu-reading-your-memorys-memory/