Re: [PATCH] drm/trigger5: Add MCT Trigger 5 USB display driver

[kernel test robot]

Hi Ho,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 3ab04dcce43cd4fdaed94f08f4e6289be4921ea4]

url:    https://github.com/intel-lab-lkp/linux/commits/Ho-Jie-Feng/drm-trigger5-Add-MCT-Trigger-5-USB-display-driver/20260911-011705
base:   3ab04dcce43cd4fdaed94f08f4e6289be4921ea4
patch link:    https://lore.kernel.org/r/20260910171709.396071-1-hjf3108%40gmail.com
patch subject: [PATCH] drm/trigger5: Add MCT Trigger 5 USB display driver
config: sparc64-allmodconfig (https://download.01.org/0day-ci/archive/20260911/202609111951.Hco6MgXH-lkp@xxxxxxxxx/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/20260911/202609111951.Hco6MgXH-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202609111951.Hco6MgXH-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/trigger5/trigger5_drv.c:435:19: warning: result of comparison of constant 65536 with expression of type 'const u16' (aka 'const unsigned short') is always false [-Wtautological-constant-out-of-range-compare]
     435 |             mode->htotal > U16_MAX + 1)
         |             ~~~~~~~~~~~~ ^ ~~~~~~~~~~~
   drivers/gpu/drm/trigger5/trigger5_drv.c:440:19: warning: result of comparison of constant 65536 with expression of type 'const u16' (aka 'const unsigned short') is always false [-Wtautological-constant-out-of-range-compare]
     440 |             mode->vtotal > U16_MAX + 1)
         |             ~~~~~~~~~~~~ ^ ~~~~~~~~~~~
   2 warnings generated.


vim +435 drivers/gpu/drm/trigger5/trigger5_drv.c

   420	
   421	static enum drm_mode_status
   422	trigger5_crtc_mode_valid(struct drm_crtc *crtc,
   423				 const struct drm_display_mode *mode)
   424	{
   425		struct trigger5_pll pll;
   426		size_t frame_len, payload_len;
   427		u64 err, ppm;
   428	
   429		/*
   430		 * The protocol stores totals, sync pulses, and back porches minus one
   431		 * in 16-bit fields.
   432		 */
   433		if (mode->hsync_end <= mode->hsync_start ||
   434		    mode->htotal <= mode->hsync_end ||
 > 435		    mode->htotal > U16_MAX + 1)
   436			return MODE_H_ILLEGAL;
   437	
   438		if (mode->vsync_end <= mode->vsync_start ||
   439		    mode->vtotal <= mode->vsync_end ||
   440		    mode->vtotal > U16_MAX + 1)
   441			return MODE_V_ILLEGAL;
   442	
   443		payload_len = array3_size(mode->hdisplay, mode->vdisplay, 3);
   444		frame_len = size_add(payload_len, sizeof(struct trigger5_bulk_header));
   445		if (frame_len > SZ_16M)
   446			return MODE_MEM;
   447	
   448		err = trigger5_calculate_pll(&pll, mode->clock);
   449		ppm = div64_u64(err * 1000, mode->clock);
   450		if (ppm > 10000)
   451			return MODE_CLOCK_RANGE;
   452	
   453		return MODE_OK;
   454	}
   455	

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