linux-kernel - Re: [PATCH 2/2] remoteproc: core: Prevent sleep when rproc crashes

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Message-ID: <20200224185334.GB9477@xps15>
Date:   Mon, 24 Feb 2020 11:53:34 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Siddharth Gupta <sidgup@...eaurora.org>
Cc:     ohad@...ery.com, bjorn.andersson@...aro.org,
        linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, tsoni@...eaurora.org,
        psodagud@...eaurora.org, rishabhb@...eaurora.org
Subject: Re: [PATCH 2/2] remoteproc: core: Prevent sleep when rproc crashes

On Wed, Feb 19, 2020 at 06:11:53PM -0800, Siddharth Gupta wrote:
> Remoteproc recovery should be fast and any delay will have an impact on the
> user-experience. Use power management APIs (pm_stay_awake and pm_relax) to
> ensure that the system does not go to sleep.

When you say "ensure the system does not go to sleep", you're referring to the
system going idle from the CPUidle subsystem? 

> 
> Signed-off-by: Siddharth Gupta <sidgup@...eaurora.org>
> ---
>  drivers/remoteproc/remoteproc_core.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 5ab65a4..52e318c 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1712,6 +1712,8 @@ static void rproc_crash_handler_work(struct work_struct *work)
>  
>  	if (!rproc->recovery_disabled)
>  		rproc_trigger_recovery(rproc);
> +
> +	pm_relax(&rproc->dev);
>  }
>  
>  /**
> @@ -2242,6 +2244,8 @@ void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type)
>  		return;
>  	}
>  
> +	pm_stay_awake(&rproc->dev);
> +

I fail to understand how this can be useful since there is no HW associted to
rproc->dev...  Is it possible for you to elaborate more on the problem you're
trying to fix?

Thanks,
Mathieu

>  	dev_err(&rproc->dev, "crash detected in %s: type %s\n",
>  		rproc->name, rproc_crash_to_string(type));
>  
> -- 
> Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project