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

From: Felipe Balbi
Date: Tue Aug 09 2016 - 05:20:11 EST



Hi,

robert.foss@xxxxxxxxxxxxx writes:
> From: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
>
> Enable runtime PM for the xhci-plat device so that the parent device
> may implement runtime PM.
>
> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
> Tested-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> ---
> 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

--
balbi

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