Re: [PATCH v4 15/21] drm/i915/flipq: Provide the nuts and bolts code for flip queue

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Jun 10, 2025 at 05:19:17AM +0800, kernel test robot wrote:
> Hi Ville,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on drm-intel/for-linux-next]
> [cannot apply to drm-intel/for-linux-next-fixes drm-tip/drm-tip linus/master v6.16-rc1 next-20250606]
> [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/Ville-Syrjala/drm-i915-dsb-Use-intel_dsb_ins_align-in-intel_dsb_align_tail/20250609-223955
> base:   git://anongit.freedesktop.org/drm-intel for-linux-next
> patch link:    https://lore.kernel.org/r/20250609141046.6244-16-ville.syrjala%40linux.intel.com
> patch subject: [PATCH v4 15/21] drm/i915/flipq: Provide the nuts and bolts code for flip queue
> config: x86_64-buildonly-randconfig-005-20250609 (https://download.01.org/0day-ci/archive/20250610/202506100537.aqJUNf0d-lkp@intel.com/config)
> compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250610/202506100537.aqJUNf0d-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/202506100537.aqJUNf0d-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
> >> drivers/gpu/drm/i915/i915.o: warning: objtool: intel_flipq_add(): unexpected end of section .text.intel_flipq_add

Given that this is clang-20, this is likely due to the potential divide
by zero that happens if intel_flipq_elem_size_dw() returns 0 in the
intel_flipq_add() -> intel_flipq_size_entries() call path. I suspect
returning 1 instead of 0 would avoid this.

Cheers,
Nathan