linux-kernel - RE: [PATCH 1/6] video: s3c-fb: Make runtime PM functional again

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Date:	Thu, 29 Dec 2011 08:54:08 +0900
From:	Jingoo Han <jg1.han@...sung.com>
To:	'Mark Brown' <broonie@...nsource.wolfsonmicro.com>,
	'Florian Tobias Schandinat' <FlorianSchandinat@....de>
Cc:	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: RE: [PATCH 1/6] video: s3c-fb: Make runtime PM functional again

> -----Original Message-----
> From: Mark Brown [mailto:broonie@...nsource.wolfsonmicro.com]
> Sent: Tuesday, December 27, 2011 11:16 PM
> To: Jingoo Han; Florian Tobias Schandinat
> Cc: linux-fbdev@...r.kernel.org; linux-kernel@...r.kernel.org; Mark Brown
> Subject: [PATCH 1/6] video: s3c-fb: Make runtime PM functional again
> 
> The change in "video: s3c-fb: modify runtime pm functions" (commit
> 35784b) renders the runtime power management for the device completely
> ineffectual as while it leaves runtime power management notionally
> enabled a runtime power reference is held for the entire time the device
> is registered meaning it will never actually do anything.
> 
> A further issue is introduced as runtime power management is added
> during the system suspend path which is not something which drivers are
> supposed to do and would interact poorly if there were any operations
> done in the runtime power management callbacks.
> 
> While this does make things simpler (the main motivation for the
> original change) it will not only cause us to use more power in the
> framebuffer controller but will also prevent us entering lower power
> domain and SoC wide states as we can never power down the domain
> containing the device.  Since neither of these things is desirable
> revert the change.
> 
> Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>

	Acked-by: Jingoo Han <jg1.han@...sung.com>

> ---
>  drivers/video/s3c-fb.c |   51 +++++++++++++++++++++++++++++------------------
>  1 files changed, 31 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
> index a0b3fd6..b1a75a0 100644
> --- a/drivers/video/s3c-fb.c
> +++ b/drivers/video/s3c-fb.c
> @@ -1038,8 +1038,30 @@ static int s3c_fb_ioctl(struct fb_info *info, unsigned int cmd,
>  	return ret;
>  }
> 
> +static int s3c_fb_open(struct fb_info *info, int user)
> +{
> +	struct s3c_fb_win *win = info->par;
> +	struct s3c_fb *sfb = win->parent;
> +
> +	pm_runtime_get_sync(sfb->dev);
> +
> +	return 0;
> +}
> +
> +static int s3c_fb_release(struct fb_info *info, int user)
> +{
> +	struct s3c_fb_win *win = info->par;
> +	struct s3c_fb *sfb = win->parent;
> +
> +	pm_runtime_put_sync(sfb->dev);
> +
> +	return 0;
> +}
> +
>  static struct fb_ops s3c_fb_ops = {
>  	.owner		= THIS_MODULE,
> +	.fb_open	= s3c_fb_open,
> +	.fb_release	= s3c_fb_release,
>  	.fb_check_var	= s3c_fb_check_var,
>  	.fb_set_par	= s3c_fb_set_par,
>  	.fb_blank	= s3c_fb_blank,
> @@ -1446,6 +1468,7 @@ static int __devinit s3c_fb_probe(struct platform_device *pdev)
>  	}
> 
>  	platform_set_drvdata(pdev, sfb);
> +	pm_runtime_put_sync(sfb->dev);
> 
>  	return 0;
> 
> @@ -1485,6 +1508,8 @@ static int __devexit s3c_fb_remove(struct platform_device *pdev)
>  	struct s3c_fb *sfb = platform_get_drvdata(pdev);
>  	int win;
> 
> +	pm_runtime_get_sync(sfb->dev);
> +
>  	for (win = 0; win < S3C_FB_MAX_WIN; win++)
>  		if (sfb->windows[win])
>  			s3c_fb_release_win(sfb, sfb->windows[win]);
> @@ -1510,7 +1535,7 @@ static int __devexit s3c_fb_remove(struct platform_device *pdev)
>  	return 0;
>  }
> 
> -#ifdef CONFIG_PM_SLEEP
> +#ifdef CONFIG_PM
>  static int s3c_fb_suspend(struct device *dev)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
> @@ -1531,8 +1556,6 @@ static int s3c_fb_suspend(struct device *dev)
>  		clk_disable(sfb->lcd_clk);
> 
>  	clk_disable(sfb->bus_clk);
> -	pm_runtime_put_sync(sfb->dev);
> -
>  	return 0;
>  }
> 
> @@ -1544,7 +1567,6 @@ static int s3c_fb_resume(struct device *dev)
>  	struct s3c_fb_win *win;
>  	int win_no;
> 
> -	pm_runtime_get_sync(sfb->dev);
>  	clk_enable(sfb->bus_clk);
> 
>  	if (!sfb->variant.has_clksel)
> @@ -1583,19 +1605,11 @@ static int s3c_fb_resume(struct device *dev)
> 
>  	return 0;
>  }
> +#else
> +#define s3c_fb_suspend NULL
> +#define s3c_fb_resume  NULL
>  #endif
> 
> -#ifdef CONFIG_PM_RUNTIME
> -static int s3c_fb_runtime_suspend(struct device *dev)
> -{
> -	return 0;
> -}
> -
> -static int s3c_fb_runtime_resume(struct device *dev)
> -{
> -	return 0;
> -}
> -#endif
> 
>  #define VALID_BPP124 (VALID_BPP(1) | VALID_BPP(2) | VALID_BPP(4))
>  #define VALID_BPP1248 (VALID_BPP124 | VALID_BPP(8))
> @@ -1918,10 +1932,7 @@ static struct platform_device_id s3c_fb_driver_ids[] = {
>  };
>  MODULE_DEVICE_TABLE(platform, s3c_fb_driver_ids);
> 
> -static const struct dev_pm_ops s3c_fb_pm_ops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(s3c_fb_suspend, s3c_fb_resume)
> -	SET_RUNTIME_PM_OPS(s3c_fb_runtime_suspend, s3c_fb_runtime_resume, NULL)
> -};
> +static UNIVERSAL_DEV_PM_OPS(s3cfb_pm_ops, s3c_fb_suspend, s3c_fb_resume, NULL);
> 
>  static struct platform_driver s3c_fb_driver = {
>  	.probe		= s3c_fb_probe,
> @@ -1930,7 +1941,7 @@ static struct platform_driver s3c_fb_driver = {
>  	.driver		= {
>  		.name	= "s3c-fb",
>  		.owner	= THIS_MODULE,
> -		.pm	= &s3c_fb_pm_ops,
> +		.pm	= &s3cfb_pm_ops,
>  	},
>  };
> 
> --
> 1.7.7.3

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