linux-kernel - Re: [PATCH] platform: chrome: Fix EC timestamp overflow

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Date:   Wed, 1 Jul 2020 11:11:26 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Gwendal Grignou <gwendal@...omium.org>, bleung@...omium.org,
        bhanumaiya@...omium.org
Cc:     groeck@...omium.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform: chrome: Fix EC timestamp overflow

Hi Gwendal,

Thank you for your patch.

On 30/6/20 9:52, Gwendal Grignou wrote:
> EC is using 32 bit timestamps (us), and before converting it to 64bit
> they were not casted, so it would overflow every 4s.
> Regular overflow every ~70 minutes was not taken into acoun either.
> 
> Signed-off-by: Gwendal Grignou <gwendal@...omium.org>

Applied for 5.9 with a slightly modified subject, platform/chrome:
cros_ec_sensorhub: ...

> ---
>  drivers/platform/chrome/cros_ec_sensorhub_ring.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/chrome/cros_ec_sensorhub_ring.c b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
> index 23960f3acc0b1..641d91088cee2 100644
> --- a/drivers/platform/chrome/cros_ec_sensorhub_ring.c
> +++ b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
> @@ -465,9 +465,7 @@ cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
>  			 * Disable filtering since we might add more jitter
>  			 * if b is in a random point in time.
>  			 */
> -			new_timestamp = fifo_timestamp -
> -					fifo_info->timestamp  * 1000 +
> -					in->timestamp * 1000;
> +			new_timestamp = c - b * 1000 + a * 1000;
>  			/*
>  			 * The timestamp can be stale if we had to use the fifo
>  			 * info timestamp.
>