From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: i2c-tools - at24 vs eeprom - decode-dimms fails with the at24 module Date: Sat, 14 Mar 2020 21:41:13 +0100 Message-ID: <20200314214113.54e48d00@endymion> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:55974 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726771AbgCOBxt (ORCPT ); Sat, 14 Mar 2020 21:53:49 -0400 In-Reply-To: Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: James Feeney Cc: linux-i2c@vger.kernel.org Hi James, On Sat, 14 Mar 2020 09:22:57 -0600, James Feeney wrote: > The log says "kernel: eeprom 3-0050: eeprom driver is deprecated, please use at24 instead", but decode-dimms will only work with the deprecated eeprom driver. With the at24 module, "Number of SDRAM DIMMs detected and decoded: 0". With the eeprom module, "Number of SDRAM DIMMs detected and decoded: 6". This is on Arch Linux, with linux 5.5.9.arch1-2, on an old Asus P6T DELUXE V2 with a Core i7. While the legacy eeprom driver (poorly) auto-detected SPD EEPROMs, the at24 driver requires SPD EEPOMs to be explicitly enumerated. There is work in progress [1] to automate this in some cases (namely x86 systems using the i2c-i801 SMBus controller driver) but for now you'll have to do it yourself from user-space. How to do that is explained in section 4 of: https://www.kernel.org/doc/Documentation/i2c/instantiating-devices TL;DR: Something like: # echo spd 0x50 > /sys/bus/i2c/devices/i2c-3/new_device should do the trick, if i2c-3 is your SMBus and you have 1 memory module in the first slot. If you have more memory modules, use "modprobe i2c-dev ; i2cdetect 0" to find out the proper addresses in the 0x50-0x57 range and repeat the command. I guess I should resubmit this patch set to make it transparent to the users. [1] https://lore.kernel.org/lkml/20191014113950.1f989ba6@endymion/ -- Jean Delvare SUSE L3 Support