From 33a581d800670e5d91e99203536d15ef7451ad69 Mon Sep 17 00:00:00 2001 From: Daniel Gibson Date: Wed, 24 Jun 2026 14:43:25 +0200 Subject: [PATCH] Documentation/arch/x86/amd-debugging: Add example for reset register The amd debugging documentation didn't state how to identify kernel log lines with information from the reset register about the cause of a previous random reboot. Add an example. Suggested-by: Mario Limonciello (AMD) Signed-off-by: Daniel Gibson Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Link: https://patch.msgid.link/20260624124326.746525-2-daniel@gibson.sh --- Documentation/arch/x86/amd-debugging.rst | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/arch/x86/amd-debugging.rst b/Documentation/arch/x86/amd-debugging.rst index d92bf59d62c7..3176a1240fee 100644 --- a/Documentation/arch/x86/amd-debugging.rst +++ b/Documentation/arch/x86/amd-debugging.rst @@ -366,3 +366,8 @@ There are 6 classes of reasons for the reboot: This information is read by the kernel at bootup and printed into the syslog. When a random reboot occurs this message can be helpful to determine the next component to debug. + +For example, if bit 19 was set, you will get a message like this in the log on +next bootup:: + + x86/amd: Previous system reset reason [0x00080000]: software wrote 0x6 to reset control register 0xCF9