Re: [PATCH v2 1/5] drm/gma500: Refactor backlight support

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 9/17/22 19:35, kernel test robot wrote:
> Hi Hans,
> 
> I love your patch! Perhaps something to improve:
> 
> [auto build test WARNING on drm-misc/drm-misc-next]
> [cannot apply to linus/master v6.0-rc5 next-20220916]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Hans-de-Goede/drm-gma500-Backlight-handling-changes/20220917-220535
> base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
> config: x86_64-allmodconfig
> compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
> reproduce (this is a W=1 build):
>         # https://github.com/intel-lab-lkp/linux/commit/ff9adbc897036a56bb7c57aa407a489db1985400
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Hans-de-Goede/drm-gma500-Backlight-handling-changes/20220917-220535
>         git checkout ff9adbc897036a56bb7c57aa407a489db1985400
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/gpu/drm/gma500/
> 
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    drivers/gpu/drm/gma500/backlight.c: In function 'gma_backlight_init':
>>> drivers/gpu/drm/gma500/backlight.c:73:37: warning: unused variable 'props' [-Wunused-variable]
>       73 |         struct backlight_properties props = {};
>          |                                     ^~~~~
>    At top level:
>>> drivers/gpu/drm/gma500/backlight.c:65:35: warning: 'gma_backlight_ops' defined but not used [-Wunused-const-variable=]
>       65 | static const struct backlight_ops gma_backlight_ops = {
>          |                                   ^~~~~~~~~~~~~~~~~
> 

This is caused by these not being used when the kernel's config does
not have CONFIG_BACKLIGHT enabled. I will send out a v3 series / v2
of this patch adding __maybe_unused to these 2 variables to fix this.

Regards,

Hans


> 
> vim +/props +73 drivers/gpu/drm/gma500/backlight.c
> 
>     64	
>   > 65	static const struct backlight_ops gma_backlight_ops = {
>     66		.get_brightness = gma_backlight_get_brightness,
>     67		.update_status  = gma_backlight_update_status,
>     68	};
>     69	
>     70	int gma_backlight_init(struct drm_device *dev)
>     71	{
>     72		struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
>   > 73		struct backlight_properties props = {};
>     74		int ret;
>     75	
>     76		dev_priv->backlight_enabled = true;
>     77		dev_priv->backlight_level = 100;
>     78	
>     79		ret = dev_priv->ops->backlight_init(dev);
>     80		if (ret)
>     81			return ret;
>     82	
>