From fee013712896a4f89a7aea635362dd3d471dd864 Mon Sep 17 00:00:00 2001 From: Packit Bot Date: May 04 2021 22:15:54 +0000 Subject: Apply patch 0002-dmidecode-Document-how-the-UUID-fields-are-interpret.patch patch_name: 0002-dmidecode-Document-how-the-UUID-fields-are-interpret.patch present_in_specfile: true --- diff --git a/man/dmidecode.8 b/man/dmidecode.8 index 33f7d33..52100a8 100644 --- a/man/dmidecode.8 +++ b/man/dmidecode.8 @@ -256,6 +256,20 @@ It is crafted to hard-code the table address at offset 0x20. .IP \(bu "\w'\(bu'u+1n" The DMI table is located at offset 0x20. +.SH UUID FORMAT +There is some ambiguity about how to interpret the UUID fields prior to SMBIOS +specification version 2.6. There was no mention of byte swapping, and RFC 4122 +says that no byte swapping should be applied by default. However, SMBIOS +specification version 2.6 (and later) explicitly states that the first 3 fields +of the UUID should be read as little-endian numbers (byte-swapped). +Furthermore, it implies that the same was already true for older versions of +the specification, even though it was not mentioned. In practice, many hardware +vendors were not byte-swapping the UUID. So, in order to preserve +compatibility, it was decided to interpret the UUID fields according to RFC +4122 (no byte swapping) when the SMBIOS version is older than 2.6, and to +interpret the first 3 fields as little-endian (byte-swapped) when the SMBIOS +version is 2.6 or later. The Linux kernel follows the same logic. + .SH FILES .I /dev/mem .br