Subject: Re: [PATCH v4] can: Convert to runtime_pm

From: Marc Kleine-Budde <[email-masked]>
Date: Wed, 07 Jan 2015 17:30:11 +0100

On 01/07/2015 04:58 PM, Sören Brinkmann wrote:
>> I think you have to convert the _remove() function, too. Have a look at
>> the gpio-zynq.c driver:
>>
>>> static int zynq_gpio_remove(struct platform_device *pdev)
>>> {
>>> 	struct zynq_gpio *gpio = platform_get_drvdata(pdev);
>>>
>>> 	pm_runtime_get_sync(&pdev->dev);
>>
>> However I don't understand why the get_sync() is here. Maybe Sören can help?
> 
> IIRC, the concern was that the remove function may be called while the device is
> runtime suspended. Hence the remove function needs to resume the device since the
> remove function may access the HW.

What about the corresponding runtime_put()? Would some counter be
unbalanced upon device removal?

Without having tested it, unloading and loading, i.e. reloading a CAN
driver is easier than reloading the gpio driver on an average embedded
system. Kedareswara please test your driver with something like:
modprobe; ifconfig up; cansend; ifconfig down; rmmod in a loop.

Marc

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