From mboxrd@z Thu Jan  1 00:00:00 1970
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Mon, 17 Mar 2014 13:41:31 +0000
Subject: Re: [PATCH] sh_eth: ensure pm_runtime cannot suspend the device during init
Message-Id: <1620453.50bv9Xb5nl@avalon>
List-Id: <linux-sh.vger.kernel.org>
References: <1394823605-31883-1-git-send-email-ben.dooks@codethink.co.uk>
In-Reply-To: <1394823605-31883-1-git-send-email-ben.dooks@codethink.co.uk>
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To: linux-sh@vger.kernel.org

Hi Ben,

On Monday 17 March 2014 13:36:33 Ben Dooks wrote:

[snip]

>  From pm_runtime.h:
> 
> static inline int pm_runtime_get_sync(struct device *dev)
> {
> 	return __pm_runtime_resume(dev, RPM_GET_PUT);
> }
> 
> static inline int pm_request_resume(struct device *dev)
> {
> 	return __pm_runtime_resume(dev, RPM_ASYNC);
> }
> 
> So it looks like pm_runtime_resume() does not protect against the
> possibility that something else may re-suspend the device.

Correct.

> I have yet to ascertain how this ends up happening with device probe, it
> seems to be very dependant on the code.

We might be doing something wrong in the driver from a runtime PM point of 
view that leads to the device being suspended. I'd like to catch that instead 
of hiding it by a pm_runtime_get_sync() call. If it turns out that we're not 
doing anything wrong then replacing pm_runtime_resume() with 
pm_runtime_get_sync() would of course be fine.

-- 
Regards,

Laurent Pinchart