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From: Andrew Chew <AChew@nvidia.com>
To: "'Guennadi Liakhovetski'" <g.liakhovetski@gmx.de>
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Date: Tue, 31 May 2011 18:58:29 -0700
Subject: RE: [PATCH 5/5 v2] [media] ov9740: Add suspend/resume
Thread-Topic: [PATCH 5/5 v2] [media] ov9740: Add suspend/resume
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> > +	/* For suspend/resume. */
> > +	struct v4l2_mbus_framefmt	current_mf;
> > +	int				current_enable;
> 
> bool?

Are you sure you want this to be a bool?  This thing is trying to shadow the "enable" parameter of the s_stream() callback, and that enable parameter is int.


> > +static int ov9740_suspend(struct soc_camera_device *icd, 
> pm_message_t state)
> > +{
> > +	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
> > +	struct ov9740_priv *priv = to_ov9740(sd);
> > +
> > +	if (priv->current_enable) {
> > +		int current_enable = priv->current_enable;
> > +
> > +		ov9740_s_stream(sd, 0);
> > +		priv->current_enable = current_enable;
> 
> You don't need the local variable, just set
> 
> 	priv->current_enable = true;

I think I do need that local variable, the way the code is arranged now.  I'm trying to save the state of enablement inside of priv->current_enable, at the time we are suspending, so it won't necessarily be true.  And one of the side effects of calling ov9740_s_stream(sd, 0) is that priv->current_enable will be set to false, which is why I save off the value of priv->current_enable, and then restore it after the call to ov9740_s_stream().


> >  static struct soc_camera_ops ov9740_ops = {
> > +	.suspend		= ov9740_suspend,
> > +	.resume			= ov9740_resume,
> 
> No, we don't want to use these, whey should disappear some 
> time... Please, 
> use .s_power() from struct v4l2_subdev_core_ops, you can check 
> http://article.gmane.org/gmane.linux.drivers.video-input-infra
> structure/33105 
> for an example. If your host is not using these ops, it has 
> to be fixed. 
> So far in the mainline only one soc-camera host driver is using these 
> callbacks: pxa_camera.c, which, looking at your email 
> address, I doubt is 
> the driver, that you're using;)

Okay, will do.  Thanks for pointing that out :)

Is the camera host driver expected to directly call the sensor driver's s_power (via v4l2_subdev_call(sd, core, s_power, <some value>)?  Or does the v4l2 framework do this for you?  I didn't see an example of this in my last pull of linux-next.--
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