Re: [PATCH] drm/radeon/rs780: prevent division by zero in refresh rate calculation

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

Hi Evgenii,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on linus/master v7.1-rc1 next-20260428]
[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/Evgenii-Burenchev/drm-radeon-rs780-prevent-division-by-zero-in-refresh-rate-calculation/20260429-055830
base:   https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next
patch link:    https://lore.kernel.org/r/20260428190318.34413-1-evg28bur%40yandex.ru
patch subject: [PATCH] drm/radeon/rs780: prevent division by zero in refresh rate calculation
config: parisc-defconfig (https://download.01.org/0day-ci/archive/20260430/202604300247.Gzeia1bh-lkp@intel.com/config)
compiler: hppa-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260430/202604300247.Gzeia1bh-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/202604300247.Gzeia1bh-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/radeon/rs780_dpm.c: In function 'rs780_get_pm_mode_parameters':
>> drivers/gpu/drm/radeon/rs780_dpm.c:66:25: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
      66 |                         if (crtc->mode.htotal && crtc->mode.vtotal)
         |                         ^~
   drivers/gpu/drm/radeon/rs780_dpm.c:68:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
      68 |                                 if (pi->refresh_rate == 0)
         |                                 ^~


vim +/if +66 drivers/gpu/drm/radeon/rs780_dpm.c

9d67006e6ebc6c Alex Deucher      2013-04-12  48  
9d67006e6ebc6c Alex Deucher      2013-04-12  49  static void rs780_get_pm_mode_parameters(struct radeon_device *rdev)
9d67006e6ebc6c Alex Deucher      2013-04-12  50  {
9d67006e6ebc6c Alex Deucher      2013-04-12  51  	struct igp_power_info *pi = rs780_get_pi(rdev);
9d67006e6ebc6c Alex Deucher      2013-04-12  52  	struct radeon_mode_info *minfo = &rdev->mode_info;
9d67006e6ebc6c Alex Deucher      2013-04-12  53  	struct drm_crtc *crtc;
9d67006e6ebc6c Alex Deucher      2013-04-12  54  	struct radeon_crtc *radeon_crtc;
9d67006e6ebc6c Alex Deucher      2013-04-12  55  	int i;
9d67006e6ebc6c Alex Deucher      2013-04-12  56  
9d67006e6ebc6c Alex Deucher      2013-04-12  57  	/* defaults */
9d67006e6ebc6c Alex Deucher      2013-04-12  58  	pi->crtc_id = 0;
9d67006e6ebc6c Alex Deucher      2013-04-12  59  	pi->refresh_rate = 60;
9d67006e6ebc6c Alex Deucher      2013-04-12  60  
9d67006e6ebc6c Alex Deucher      2013-04-12  61  	for (i = 0; i < rdev->num_crtc; i++) {
9d67006e6ebc6c Alex Deucher      2013-04-12  62  		crtc = (struct drm_crtc *)minfo->crtcs[i];
9d67006e6ebc6c Alex Deucher      2013-04-12  63  		if (crtc && crtc->enabled) {
9d67006e6ebc6c Alex Deucher      2013-04-12  64  			radeon_crtc = to_radeon_crtc(crtc);
9d67006e6ebc6c Alex Deucher      2013-04-12  65  			pi->crtc_id = radeon_crtc->crtc_id;
9d67006e6ebc6c Alex Deucher      2013-04-12 @66  			if (crtc->mode.htotal && crtc->mode.vtotal)
c3eaa088277709 Alex Deucher      2013-09-13  67  				pi->refresh_rate = drm_mode_vrefresh(&crtc->mode);
0d99a77de43b3f Evgenii Burenchev 2026-04-28  68  				if (pi->refresh_rate == 0)
0d99a77de43b3f Evgenii Burenchev 2026-04-28  69  					pi->refresh_rate = 60;
9d67006e6ebc6c Alex Deucher      2013-04-12  70  			break;
9d67006e6ebc6c Alex Deucher      2013-04-12  71  		}
9d67006e6ebc6c Alex Deucher      2013-04-12  72  	}
9d67006e6ebc6c Alex Deucher      2013-04-12  73  }
9d67006e6ebc6c Alex Deucher      2013-04-12  74  

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