Re: [PATCH v4 68/80] drm/panel: panel-dsi-cm: remove extra 'if'

[kernel test robot <lkp@intel.com>]

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Hi Tomi,

I love your patch! Perhaps something to improve:

[auto build test WARNING on omap/for-next]
[also build test WARNING on robh/for-next balbi-usb/testing/next linus/master v5.10-rc6]
[cannot apply to next-20201201]
[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]

url:    https://github.com/0day-ci/linux/commits/Tomi-Valkeinen/Convert-DSI-code-to-use-drm_mipi_dsi-and-drm_panel/20201124-205129
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git for-next
config: riscv-randconfig-r016-20201202 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 2671fccf0381769276ca8246ec0499adcb9b0355)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/0day-ci/linux/commit/09d304dc23e60a46580ec8a3d7db7210138fc9db
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Tomi-Valkeinen/Convert-DSI-code-to-use-drm_mipi_dsi-and-drm_panel/20201124-205129
        git checkout 09d304dc23e60a46580ec8a3d7db7210138fc9db
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/panel/panel-dsi-cm.c:210:6: warning: variable 'r' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (ddata->enabled)
               ^~~~~~~~~~~~~~
   drivers/gpu/drm/panel/panel-dsi-cm.c:216:9: note: uninitialized use occurs here
           return r;
                  ^
   drivers/gpu/drm/panel/panel-dsi-cm.c:210:2: note: remove the 'if' if its condition is always true
           if (ddata->enabled)
           ^~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/panel/panel-dsi-cm.c:197:7: note: initialize the variable 'r' to silence this warning
           int r;
                ^
                 = 0
   1 warning generated.

vim +210 drivers/gpu/drm/panel/panel-dsi-cm.c

   193	
   194	static int dsicm_bl_update_status(struct backlight_device *dev)
   195	{
   196		struct panel_drv_data *ddata = dev_get_drvdata(&dev->dev);
   197		int r;
   198		int level;
   199	
   200		if (dev->props.fb_blank == FB_BLANK_UNBLANK &&
   201				dev->props.power == FB_BLANK_UNBLANK)
   202			level = dev->props.brightness;
   203		else
   204			level = 0;
   205	
   206		dev_dbg(&ddata->dsi->dev, "update brightness to %d\n", level);
   207	
   208		mutex_lock(&ddata->lock);
   209	
 > 210		if (ddata->enabled)
   211			r = dsicm_dcs_write_1(ddata, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
   212					      level);
   213	
   214		mutex_unlock(&ddata->lock);
   215	
   216		return r;
   217	}
   218	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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