Re: [PATCH 1/4] drm/i915/psr: Add helper for checking if vblank evasion is needed by PSR

Re: [PATCH 1/4] drm/i915/psr: Add helper for checking if vblank evasion is needed by PSR

[kernel test robot]

Hi Jouni,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20251124]
[cannot apply to drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-tip/drm-tip v6.18-rc7 v6.18-rc6 v6.18-rc5 linus/master v6.18-rc7]
[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-i915-psr-Add-helper-for-checking-if-vblank-evasion-is-needed-by-PSR/20251125-143352
base:   next-20251124
patch link:    https://lore.kernel.org/r/20251125063253.328023-2-jouni.hogander%40intel.com
patch subject: [PATCH 1/4] drm/i915/psr: Add helper for checking if vblank evasion is needed by PSR
config: x86_64-randconfig-003-20251126 (https://download.01.org/0day-ci/archive/20251126/202511262156.H5YJpnc5-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251126/202511262156.H5YJpnc5-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/202511262156.H5YJpnc5-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/i915/display/intel_psr.c:4550:2: warning: variable 'intel_dp' is used uninitialized whenever 'for' loop exits because its condition is false [-Wsometimes-uninitialized]
    4550 |         for_each_intel_encoder_mask_with_psr(display->drm, encoder,
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    4551 |                                              crtc_state->uapi.encoder_mask) {
         |                                              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/i915/display/intel_display.h:271:2: note: expanded from macro 'for_each_intel_encoder_mask_with_psr'
     271 |         list_for_each_entry((intel_encoder), &(dev)->mode_config.encoder_list, base.head) \
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/list.h:783:7: note: expanded from macro 'list_for_each_entry'
     783 |              !list_entry_is_head(pos, head, member);                    \
         |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/i915/display/intel_psr.c:4556:9: note: uninitialized use occurs here
    4556 |         return intel_dp->psr.psr2_sel_fetch_enabled;
         |                ^~~~~~~~
   drivers/gpu/drm/i915/display/intel_psr.c:4550:2: note: remove the condition if it is always true
    4550 |         for_each_intel_encoder_mask_with_psr(display->drm, encoder,
         |         ^
   drivers/gpu/drm/i915/display/intel_display.h:271:2: note: expanded from macro 'for_each_intel_encoder_mask_with_psr'
     271 |         list_for_each_entry((intel_encoder), &(dev)->mode_config.encoder_list, base.head) \
         |         ^
   include/linux/list.h:783:7: note: expanded from macro 'list_for_each_entry'
     783 |              !list_entry_is_head(pos, head, member);                    \
         |              ^
   drivers/gpu/drm/i915/display/intel_psr.c:4548:27: note: initialize the variable 'intel_dp' to silence this warning
    4548 |         struct intel_dp *intel_dp;
         |                                  ^
         |                                   = NULL
   1 warning generated.


vim +4550 drivers/gpu/drm/i915/display/intel_psr.c

  4543	
  4544	bool intel_psr_needs_evasion(const struct intel_crtc_state *crtc_state)
  4545	{
  4546		struct intel_display *display = to_intel_display(crtc_state);
  4547		struct intel_encoder *encoder;
  4548		struct intel_dp *intel_dp;
  4549	
> 4550		for_each_intel_encoder_mask_with_psr(display->drm, encoder,

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