linux-kernel - Re: [PATCH v2] can: Fix bug in suspend/resume

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Message-ID: <54662129.3020907@pengutronix.de>
Date:	Fri, 14 Nov 2014 16:35:05 +0100
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	Sören Brinkmann <soren.brinkmann@...inx.com>
CC:	Kedareswara rao Appana <appana.durga.rao@...inx.com>,
	wg@...ndegger.com, michal.simek@...inx.com,
	grant.likely@...aro.org, robh+dt@...nel.org,
	linux-can@...r.kernel.org, netdev@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Kedareswara rao Appana <appanad@...inx.com>
Subject: Re: [PATCH v2] can: Fix bug in suspend/resume

On 11/14/2014 04:20 PM, Sören Brinkmann wrote:
>>>> Please look the at suspend/resume code and count the
>>>> clock_enable/disable manually. After a suspend/resume cycle, you have
>>>> enabled the clock twice, but disabled it once.
>>>>
>>>> I think you have to abstract the clock handling behind runtime PM. I
>>>> haven't done this myself yet, but the strong feeling that this is a
>>>> possible solution to your problem. These links might help:
>>>
>>> I agree, the clock handling looks weird. Also the clk_disable calls in
>>> xcan_get_berr_counter() look suspicious to me, but I might be wrong.
>>> I think you can take a look at gpio-zynq for an example for runtime_pm
>>> usage. I think the usage model in that driver is similar to here.
>>
>> The xcan_get_berr_counter() function is correct, when doing manual (i.e.
>> non runtime-pm) clock handling. This function might be called if the
>> interface is down, this means clocks are disabled.
> 
> I see, thanks for the clarification. Guess that should become
> pm_runtime_get_sync() and pm_runtime_put() when converting to
> runtime_pm.

Yes, as far as I understand runtime pm.

Marc

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