linux-kernel - [PATCH] platform/x86: amd-pmc: Increase the response register timeout

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210914020115.655-1-mario.limonciello@amd.com>
Date:   Mon, 13 Sep 2021 21:01:14 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        Hans de Goede <hdegoede@...hat.com>
CC:     Mario Limonciello <mario.limonciello@....com>, <stable@...nel.org>,
        "Julian Sikorski" <belegdol@...il.com>,
        Mark Gross <mgross@...ux.intel.com>,
        "open list:AMD PMC DRIVER" <platform-driver-x86@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: [PATCH] platform/x86: amd-pmc: Increase the response register timeout

There have been reports of approximately a 0.9%-1.7% failure rate in SMU
communication timeouts with s0i3 entry on some OEM designs.  Currently
the design in amd-pmc is to try every 100us for up to 20ms.

However the GPU driver which also communicates with the SMU using a
mailbox register which the driver polls every 1us for up to 2000ms.
In the GPU driver this was increased by commit 055162645a40 ("drm/amd/pm:
increase time out value when sending msg to SMU")

Increase the maximum timeout used by amd-pmc to 2000ms to match this
behavior.  This has been shown to improve the stability for machines
that randomly have failures.

Cc: stable@...nel.org
Reported-by: Julian Sikorski <belegdol@...il.com>
BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1629
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/platform/x86/amd-pmc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
index 3481479a2942..d6a7c896ac86 100644
--- a/drivers/platform/x86/amd-pmc.c
+++ b/drivers/platform/x86/amd-pmc.c
@@ -71,7 +71,7 @@
 #define AMD_CPU_ID_YC			0x14B5

 #define PMC_MSG_DELAY_MIN_US		100
-#define RESPONSE_REGISTER_LOOP_MAX	200
+#define RESPONSE_REGISTER_LOOP_MAX	20000

 #define SOC_SUBSYSTEM_IP_MAX	12
 #define DELAY_MIN_US		2000
-- 
2.25.1