Re: [PATCH 2/2] media: i2c: Add driver for Aptina MT9V111

[kbuild test robot]

Hi Jacopo,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linuxtv-media/master]
[also build test WARNING on v4.17 next-20180608]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Jacopo-Mondi/media-i2c-mt9v111-sensor-driver/20180611-233038
base:   git://linuxtv.org/media_tree.git master
config: sh-allmodconfig (attached as .config)
compiler: sh4-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=sh 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/media/i2c/mt9v111.c: In function 'mt9v111_set_format':
>> drivers/media/i2c/mt9v111.c:929:15: warning: 'idx' may be used uninitialized in this function [-Wmaybe-uninitialized]
     unsigned int idx;
                  ^~~

vim +/idx +929 drivers/media/i2c/mt9v111.c

   920	
   921	static int mt9v111_set_format(struct v4l2_subdev *subdev,
   922				      struct v4l2_subdev_pad_config *cfg,
   923				      struct v4l2_subdev_format *format)
   924	{
   925		struct mt9v111_dev *mt9v111 = sd_to_mt9v111(subdev);
   926		struct v4l2_mbus_framefmt new_fmt;
   927		struct v4l2_mbus_framefmt *__fmt;
   928		unsigned int best_fit = ~0L;
 > 929		unsigned int idx;
   930		unsigned int i;
   931	
   932		mutex_lock(&mt9v111->stream_mutex);
   933		if (mt9v111->streaming) {
   934			mutex_unlock(&mt9v111->stream_mutex);
   935			return -EBUSY;
   936		}
   937		mutex_unlock(&mt9v111->stream_mutex);
   938	
   939		if (format->pad)
   940			return -EINVAL;
   941	
   942		/* Update mbus format code and sizes. */
   943		for (i = 0; i < ARRAY_SIZE(mt9v111_formats); i++) {
   944			if (format->format.code == mt9v111_formats[i].code) {
   945				new_fmt.code = mt9v111_formats[i].code;
   946				break;
   947			}
   948		}
   949		if (i == ARRAY_SIZE(mt9v111_formats))
   950			new_fmt.code = mt9v111_formats[0].code;
   951	
   952		for (i = 0; i < ARRAY_SIZE(mt9v111_frame_sizes); i++) {
   953			unsigned int fit = abs(mt9v111_frame_sizes[i].width -
   954					       format->format.width) +
   955					   abs(mt9v111_frame_sizes[i].height -
   956					       format->format.height);
   957			if (fit < best_fit) {
   958				best_fit = fit;
   959				idx = i;
   960	
   961				if (fit == 0)
   962					break;
   963			}
   964		}
   965		new_fmt.width = mt9v111_frame_sizes[idx].width;
   966		new_fmt.height = mt9v111_frame_sizes[idx].height;
   967	
   968		/* Update the device (or pad) format if it has changed. */
   969		__fmt = __mt9v111_get_pad_format(mt9v111, cfg, format->pad,
   970						 format->which);
   971	
   972		/* Format hasn't changed, stop here. */
   973		if (__fmt->code == new_fmt.code &&
   974		    __fmt->width == new_fmt.width &&
   975		    __fmt->height == new_fmt.height)
   976			goto done;
   977	
   978		/* Update the format and sizes, then  mark changes as pending. */
   979		__fmt->code = new_fmt.code;
   980		__fmt->width = new_fmt.width;
   981		__fmt->height = new_fmt.height;
   982	
   983		if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
   984			mt9v111->pending = true;
   985	
   986		dev_info(mt9v111->dev, "%s: mbus_code: %x - (%ux%u)\n",
   987			 __func__, __fmt->code, __fmt->width, __fmt->height);
   988	
   989	done:
   990		format->format = *__fmt;
   991	
   992		return 0;
   993	}
   994	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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