[pci:vga 3/5] drivers/gpu/drm/i915/display/intel_vga.c:68:2: error: ignoring return value of function declared with 'warn_unused_result' attribute

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

Hi Simon,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git vga
head:   21b082bd2a45704a6f7e69c190c8287a3d011ea9
commit: dc582b5ed4b749335b947258d4874df628726632 [3/5] PCI/VGA: Mark vga_get() and wrappers as __must_check
config: x86_64-randconfig-011-20260329 (https://download.01.org/0day-ci/archive/20260330/202603300336.G53JumVL-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/20260330/202603300336.G53JumVL-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/202603300336.G53JumVL-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/i915/display/intel_vga.c:68:2: error: ignoring return value of function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
      68 |         vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
         |         ^~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/i915/display/intel_vga.c:93:2: error: ignoring return value of function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
      93 |         vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
         |         ^~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~
   2 errors generated.


vim +/warn_unused_result +68 drivers/gpu/drm/i915/display/intel_vga.c

0c80d60ae63461 Ville Syrjälä 2025-04-17  43  
4fb8783165b7c6 Jani Nikula   2019-10-01  44  /* Disable the VGA plane that we never use */
4b6e05c43b7542 Ville Syrjälä 2024-09-06  45  void intel_vga_disable(struct intel_display *display)
4fb8783165b7c6 Jani Nikula   2019-10-01  46  {
4b6e05c43b7542 Ville Syrjälä 2024-09-06  47  	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
4b6e05c43b7542 Ville Syrjälä 2024-09-06  48  	i915_reg_t vga_reg = intel_vga_cntrl_reg(display);
0c80d60ae63461 Ville Syrjälä 2025-04-17  49  	enum pipe pipe;
0c80d60ae63461 Ville Syrjälä 2025-04-17  50  	u32 tmp;
4fb8783165b7c6 Jani Nikula   2019-10-01  51  	u8 sr1;
4fb8783165b7c6 Jani Nikula   2019-10-01  52  
0c80d60ae63461 Ville Syrjälä 2025-04-17  53  	tmp = intel_de_read(display, vga_reg);
0c80d60ae63461 Ville Syrjälä 2025-04-17  54  	if (tmp & VGA_DISP_DISABLE)
a3af0140663dc3 Emil Velikov  2021-06-04  55  		return;
a3af0140663dc3 Emil Velikov  2021-06-04  56  
0c80d60ae63461 Ville Syrjälä 2025-04-17  57  	if (display->platform.cherryview)
0c80d60ae63461 Ville Syrjälä 2025-04-17  58  		pipe = REG_FIELD_GET(VGA_PIPE_SEL_MASK_CHV, tmp);
0c80d60ae63461 Ville Syrjälä 2025-04-17  59  	else if (has_vga_pipe_sel(display))
0c80d60ae63461 Ville Syrjälä 2025-04-17  60  		pipe = REG_FIELD_GET(VGA_PIPE_SEL_MASK, tmp);
0c80d60ae63461 Ville Syrjälä 2025-04-17  61  	else
0c80d60ae63461 Ville Syrjälä 2025-04-17  62  		pipe = PIPE_A;
0c80d60ae63461 Ville Syrjälä 2025-04-17  63  
0c80d60ae63461 Ville Syrjälä 2025-04-17  64  	drm_dbg_kms(display->drm, "Disabling VGA plane on pipe %c\n",
0c80d60ae63461 Ville Syrjälä 2025-04-17  65  		    pipe_name(pipe));
0c80d60ae63461 Ville Syrjälä 2025-04-17  66  
4fb8783165b7c6 Jani Nikula   2019-10-01  67  	/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
4fb8783165b7c6 Jani Nikula   2019-10-01 @68  	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
f0bb41fad02e03 Jani Nikula   2022-02-02  69  	outb(0x01, VGA_SEQ_I);
f0bb41fad02e03 Jani Nikula   2022-02-02  70  	sr1 = inb(VGA_SEQ_D);
f0bb41fad02e03 Jani Nikula   2022-02-02  71  	outb(sr1 | VGA_SR01_SCREEN_OFF, VGA_SEQ_D);
4fb8783165b7c6 Jani Nikula   2019-10-01  72  	vga_put(pdev, VGA_RSRC_LEGACY_IO);
4fb8783165b7c6 Jani Nikula   2019-10-01  73  	udelay(300);
4fb8783165b7c6 Jani Nikula   2019-10-01  74  
4b6e05c43b7542 Ville Syrjälä 2024-09-06  75  	intel_de_write(display, vga_reg, VGA_DISP_DISABLE);
4b6e05c43b7542 Ville Syrjälä 2024-09-06  76  	intel_de_posting_read(display, vga_reg);
4fb8783165b7c6 Jani Nikula   2019-10-01  77  }
4fb8783165b7c6 Jani Nikula   2019-10-01  78  

:::::: The code at line 68 was first introduced by commit
:::::: 4fb8783165b7c6fb4b52428dbb80da8554e5fd1e drm/i915/display: abstract all vgaarb access to intel_vga.[ch]

:::::: TO: Jani Nikula <jani.nikula@intel.com>
:::::: CC: Jani Nikula <jani.nikula@intel.com>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki