[PATCH 4/6] drm/i915/psr: Silence period and lfps half cycle

[kernel test robot]

Hi Jouni,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on drm-tip/drm-tip next-20240215]
[cannot apply to drm-intel/for-linux-next-fixes drm/drm-next linus/master v6.8-rc4]
[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/Jouni-H-gander/drm-display-Add-missing-aux-less-alpm-wake-related-bits/20240215-185209
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
patch link:    https://lore.kernel.org/r/20240215104934.2395239-5-jouni.hogander%40intel.com
patch subject: [PATCH 4/6] drm/i915/psr: Silence period and lfps half cycle
config: i386-buildonly-randconfig-004-20240215 (https://download.01.org/0day-ci/archive/20240216/202402161056.O7eY8Uvv-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240216/202402161056.O7eY8Uvv-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202402161056.O7eY8Uvv-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/i915/display/intel_psr.c:1253:6: warning: variable 'silence_period' is uninitialized when used here [-Wuninitialized]
    1253 |             silence_period > 256 || silence_period < 0 ||
         |             ^~~~~~~~~~~~~~
   drivers/gpu/drm/i915/display/intel_psr.c:1240:17: note: initialize the variable 'silence_period' to silence this warning
    1240 |                 silence_period, lfps_half_cycle;
         |                               ^
         |                                = 0
   1 warning generated.


vim +/silence_period +1253 drivers/gpu/drm/i915/display/intel_psr.c

  1234	
  1235	static int _lnl_compute_aux_less_alpm_params(struct intel_dp *intel_dp,
  1236						     struct intel_crtc_state *crtc_state)
  1237	{
  1238		struct drm_i915_private *i915 = dp_to_i915(intel_dp);
  1239		int aux_less_wake_time, aux_less_wake_lines, switch_to_active_lines,
  1240			silence_period, lfps_half_cycle;
  1241	
  1242		aux_less_wake_time =
  1243			_lnl_compute_aux_less_wake_time(crtc_state->port_clock / 1000);
  1244		aux_less_wake_lines = intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode,
  1245							       aux_less_wake_time);
  1246	
  1247		switch_to_active_lines =
  1248			intel_usecs_to_scanlines(
  1249				&crtc_state->hw.adjusted_mode,
  1250				_lnl_compute_switch_to_active_time(crtc_state->port_clock / 1000));
  1251	
  1252		if (aux_less_wake_lines > 32 || switch_to_active_lines > 32 ||
> 1253		    silence_period > 256 || silence_period < 0 ||
  1254		    !_lnl_get_silence_period_and_lfps_half_cycle(intel_dp->link_rate,
  1255								 &silence_period,
  1256								 &lfps_half_cycle))
  1257			return false;
  1258	
  1259		if (i915->display.params.psr_safest_params) {
  1260			aux_less_wake_lines = 32;
  1261			switch_to_active_lines = 32;
  1262		}
  1263	
  1264		intel_dp->psr.alpm_parameters.aux_less_wake_lines = aux_less_wake_lines;
  1265		intel_dp->psr.alpm_parameters.switch_to_active_lines = switch_to_active_lines;
  1266		intel_dp->psr.alpm_parameters.silence_period_sym_clocks = silence_period;
  1267		intel_dp->psr.alpm_parameters.lfps_half_cycle_num_of_syms = lfps_half_cycle;
  1268	
  1269		return true;
  1270	}
  1271	

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