linux-kernel - Re: mfd: cros_ec: Check for mkbp events on resume only if supported.

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Date:   Tue, 21 Aug 2018 09:28:17 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     RaviChandra Sadineni <ravisadineni@...omium.org>,
        lee.jones@...aro.org, dmitry.torokhov@...il.com,
        ravisadineni@...gle.com, dtor@...gle.com,
        linux-samsung-soc@...r.kernel.org, tbroch@...gle.com,
        linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
        tfiga@...omium.org
Subject: Re: mfd: cros_ec: Check for mkbp events on resume only if
 supported.

Hi Ravi,

On 2018-08-20 17:34, RaviChandra Sadineni wrote:
> Currently on every resume we check for mkbp events and notify the
> clients. This helps in identifying the wakeup sources. But on devices
> that do not support mkbp protocol, we might end up querying key state of
> the keyboard in a loop which blocks the resume. Instead check for events
> only if mkbp is supported.
>
> Signed-off-by: RaviChandra Sadineni <ravisadineni@...omium.org>

Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

> ---
>
>   Note: This patch fixes the suspend/resume issue on Snow and Peach-Pit
>   Chromebooks, both on vanilla v4.18 as well as linux-next from 20 August
>   2018. Further info at: https://lkml.org/lkml/2018/6/5/1076
>   
>   drivers/mfd/cros_ec.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> index 65a9757a6d21..fe6f83766144 100644
> --- a/drivers/mfd/cros_ec.c
> +++ b/drivers/mfd/cros_ec.c
> @@ -218,7 +218,8 @@ EXPORT_SYMBOL(cros_ec_suspend);
>   
>   static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
>   {
> -	while (cros_ec_get_next_event(ec_dev, NULL) > 0)
> +	while (ec_dev->mkbp_event_supported &&
> +	       cros_ec_get_next_event(ec_dev, NULL) > 0)
>   		blocking_notifier_call_chain(&ec_dev->event_notifier,
>   					     1, ec_dev);
>   }

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland