linux-kernel - Re: [PACTH v3 1/2] usb: xhci: plat: Enable runtime PM

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Date:	Tue, 9 Aug 2016 11:31:47 -0400
From:	Robert Foss <robert.foss@...labora.com>
To:	Felipe Balbi <felipe.balbi@...ux.intel.com>,
	mathias.nyman@...el.com, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Julius Werner <jwerner@...omium.org>,
	Andrew Bresticker <abrestic@...omium.org>
Subject: Re: [PACTH v3 1/2] usb: xhci: plat: Enable runtime PM



On 2016-08-09 05:19 AM, Felipe Balbi wrote:
>
> Hi,
>
> robert.foss@...labora.com writes:
>> From: Andrew Bresticker <abrestic@...omium.org>
>>
>> Enable runtime PM for the xhci-plat device so that the parent device
>> may implement runtime PM.
>>
>> Signed-off-by: Andrew Bresticker <abrestic@...omium.org>
>> Tested-by: Robert Foss <robert.foss@...labora.com>
>> Signed-off-by: Robert Foss <robert.foss@...labora.com>
>> ---
>>  drivers/usb/host/xhci-plat.c | 24 ++++++++++++++++++++++--
>>  1 file changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
>> index ed56bf9..4f39d4e 100644
>> --- a/drivers/usb/host/xhci-plat.c
>> +++ b/drivers/usb/host/xhci-plat.c
>> @@ -246,6 +246,9 @@ static int xhci_plat_probe(struct platform_device *pdev)
>>  	if (ret)
>>  		goto dealloc_usb2_hcd;
>>
>> +	pm_runtime_set_active(&pdev->dev);
>> +	pm_runtime_enable(&pdev->dev);
>> +
>>  	return 0;
>>
>>
>> @@ -274,6 +277,8 @@ static int xhci_plat_remove(struct platform_device *dev)
>>  	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
>>  	struct clk *clk = xhci->clk;
>>
>> +	pm_runtime_disable(&dev->dev);
>> +
>>  	usb_remove_hcd(xhci->shared_hcd);
>>  	usb_phy_shutdown(hcd->usb_phy);
>>
>> @@ -292,7 +297,11 @@ static int xhci_plat_suspend(struct device *dev)
>>  {
>>  	struct usb_hcd	*hcd = dev_get_drvdata(dev);
>>  	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
>> +	int ret;
>>
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret < 0)
>> +		return ret;
>
> you're leaving unbalanced PM usage_counter here. If pm_runtime_get*()
> fails, you still have to decrement usage_counter.
>
>>  	/*
>>  	 * xhci_suspend() needs `do_wakeup` to know whether host is allowed
>>  	 * to do wakeup during suspend. Since xhci_plat_suspend is currently
>> @@ -301,15 +310,26 @@ static int xhci_plat_suspend(struct device *dev)
>>  	 * reconsider this when xhci_plat_suspend enlarges its scope, e.g.,
>>  	 * also applies to runtime suspend.
>>  	 */
>> -	return xhci_suspend(xhci, device_may_wakeup(dev));
>> +	ret = xhci_suspend(xhci, device_may_wakeup(dev));
>> +	pm_runtime_put(dev);
>> +
>> +	return ret;
>>  }
>>
>>  static int xhci_plat_resume(struct device *dev)
>>  {
>>  	struct usb_hcd	*hcd = dev_get_drvdata(dev);
>>  	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
>> +	int ret;
>> +
>> +	ret = pm_runtime_get_sync(dev);
>> +	if (ret < 0)
>> +		return ret;
>
> ditto
>

Thanks Filipe!
I'll be submitting a v4 as soon as testing has completed.