linux-kernel - Re: [PATCH] platform/chrome: cros_ec: Expose suspend

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Date:   Mon, 8 Aug 2022 06:07:07 +0000
From:   Tzung-Bi Shih <tzungbi@...nel.org>
To:     Evan Green <evgreen@...omium.org>
Cc:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Rajat Jain <rajatja@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Prashant Malani <pmalani@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Tinghan Shen <tinghan.shen@...iatek.com>,
        chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform/chrome: cros_ec: Expose suspend_timeout in
 debugfs

On Fri, Aug 05, 2022 at 03:17:17PM -0700, Evan Green wrote:
> diff --git a/Documentation/ABI/testing/debugfs-cros-ec b/Documentation/ABI/testing/debugfs-cros-ec
> index 1fe0add99a2a99..8e7e76e6481550 100644
> --- a/Documentation/ABI/testing/debugfs-cros-ec
> +++ b/Documentation/ABI/testing/debugfs-cros-ec
> @@ -54,3 +54,25 @@ Description:
>  		this feature.
>  
>  		Output will be in the format: "0x%08x\n".
> +
> +What:		/sys/kernel/debug/<cros-ec-device>/suspend_timeout
> +Date:		August 2022
> +KernelVersion:	6.0

The merge window is opened.  It's too late for the patch if the following
outcome version is 6.0.

> +Description:
> +		Some ECs have a feature where they will track transitions to the
> +		a hardware-controlled sleep line, such as Intel's SLP_S0 line,
> +		in order to detect cases where a system failed to go into deep
> +		sleep states. The suspend_timeout file controls the amount of
> +		time in milliseconds the EC will wait before declaring a sleep
> +		timeout event and attempting to wake the system.
> +
> +		Supply 0 to use the default value coded into EC firmware. Supply
> +		65535 to disable the EC sleep failure detection mechanism.

Better to mention EC_HOST_SLEEP_TIMEOUT_INFINITE or [1] in the description.
Or, it's not obvious from the patch that 65535 disables the mechanism. 

[1]: https://chromium.googlesource.com/chromiumos/platform/ec/+/refs/heads/main/power/host_sleep.c