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

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Message-ID: <666c9ae0-68d5-6008-6fc8-05d097fe3023@amd.com>
Date:   Tue, 14 Sep 2021 14:08:21 +0530
From:   Shyam Sundar S K <Shyam-sundar.S-k@....com>
To:     Mario Limonciello <mario.limonciello@....com>,
        Hans de Goede <hdegoede@...hat.com>
Cc:     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: Re: [PATCH] platform/x86: amd-pmc: Increase the response register
 timeout



On 9/14/2021 7:31 AM, Mario Limonciello wrote:
> 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
> 

Looks good to me.

Acked-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>