Re: [PATCH 3/3] drm/i915/de: Implement register polling in the display code

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

Hi Ville,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-i915/for-linux-next]
[also build test WARNING on drm-tip/drm-tip next-20260311]
[cannot apply to drm-i915/for-linux-next-fixes drm-xe/drm-xe-next linus/master v7.0-rc3]
[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/Ville-Syrjala/drm-i915-de-Introduce-intel_de-c-and-move-intel_de_-read-write-8-there/20260314-004939
base:   https://gitlab.freedesktop.org/drm/i915/kernel.git for-linux-next
patch link:    https://lore.kernel.org/r/20260313111028.25159-4-ville.syrjala%40linux.intel.com
patch subject: [PATCH 3/3] drm/i915/de: Implement register polling in the display code
config: sparc64-allmodconfig (https://download.01.org/0day-ci/archive/20260314/202603141514.jgf9tlEy-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 7d47b695929cc7f85eeb0f87d0189adc04c1c629)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260314/202603141514.jgf9tlEy-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603141514.jgf9tlEy-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/i915/display/intel_de.c:72:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
      72 |         if (fast_timeout_us)
         |             ^~~~~~~~~~~~~~~
   drivers/gpu/drm/i915/display/intel_de.c:77:6: note: uninitialized use occurs here
      77 |         if (ret && slow_timeout_us)
         |             ^~~
   drivers/gpu/drm/i915/display/intel_de.c:72:2: note: remove the 'if' if its condition is always true
      72 |         if (fast_timeout_us)
         |         ^~~~~~~~~~~~~~~~~~~~
      73 |                 ret = __intel_de_wait_for_register(display, reg, mask, value,
   drivers/gpu/drm/i915/display/intel_de.c:70:9: note: initialize the variable 'ret' to silence this warning
      70 |         int ret;
         |                ^
         |                 = 0
   1 warning generated.


vim +72 drivers/gpu/drm/i915/display/intel_de.c

    62	
    63	static int intel_de_wait_for_register(struct intel_display *display,
    64					      i915_reg_t reg, u32 mask, u32 value,
    65					      unsigned int fast_timeout_us,
    66					      unsigned int slow_timeout_us,
    67					      u32 (*read)(struct intel_display *display, i915_reg_t reg),
    68					      u32 *out_value, bool is_atomic)
    69	{
    70		int ret;
    71	
  > 72		if (fast_timeout_us)
    73			ret = __intel_de_wait_for_register(display, reg, mask, value,
    74							   fast_timeout_us, read,
    75							   out_value, is_atomic);
    76	
    77		if (ret && slow_timeout_us)
    78			ret = __intel_de_wait_for_register(display, reg, mask, value,
    79							   slow_timeout_us, read,
    80							   out_value, is_atomic);
    81	
    82		return ret;
    83	}
    84	

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