Re: [PATCH v3 2/2] [media] uvcvideo: Remain runtime-suspended at sleeps

From: Alan Stern
Date: Fri Apr 17 2015 - 13:32:55 EST


On Fri, 17 Apr 2015, Tomeu Vizoso wrote:

> When the system goes to sleep and afterwards resumes, a significant
> amount of time is spent suspending and resuming devices that were
> already runtime-suspended.
>
> By setting the power.force_direct_complete flag, the PM core will ignore
> the state of descendant devices and the device will be let in
> runtime-suspend.
>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_driver.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 5970dd6..ae75a70 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -1945,6 +1945,8 @@ static int uvc_probe(struct usb_interface *intf,
> "supported.\n", ret);
> }
>
> + intf->dev.parent->power.force_direct_complete = true;

This seems wrong. The uvc driver is bound to intf, not to intf's
parent. So it would be okay for the driver to set
intf->dev.power.force_direct_complete, but it's wrong to set
intf->dev.parent->power.force_direct_complete.

Alan Stern

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