Hi Imre, kernel test robot noticed the following build errors: [auto build test ERROR on drm-tip/drm-tip] url: https://github.com/intel-lab-lkp/linux/commits/Imre-Deak/drm-dp_mst-Fix-fractional-DSC-bpp-handling/20231024-091920 base: git://anongit.freedesktop.org/drm/drm-tip drm-tip patch link: https://lore.kernel.org/r/20231024010925.3949910-9-imre.deak%40intel.com patch subject: [PATCH 08/29] drm/dp: Add helpers to calculate the link BW overhead config: arm-s5pv210_defconfig (https://download.01.org/0day-ci/archive/20231025/202310252345.i0qKzGuh-lkp@xxxxxxxxx/config) compiler: arm-linux-gnueabi-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231025/202310252345.i0qKzGuh-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/202310252345.i0qKzGuh-lkp@xxxxxxxxx/ All errors (new ones prefixed by >>): arm-linux-gnueabi-ld: drivers/gpu/drm/display/drm_dp_mst_topology.o: in function `drm_dp_calc_pbn_mode': >> drivers/gpu/drm/display/drm_dp_mst_topology.c:4745:(.text+0x12b0): undefined reference to `drm_dp_bw_overhead' vim +4745 drivers/gpu/drm/display/drm_dp_mst_topology.c 4718 4719 /** 4720 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode. 4721 * @clock: dot clock 4722 * @bpp: bpp as .4 binary fixed point 4723 * 4724 * This uses the formula in the spec to calculate the PBN value for a mode. 4725 */ 4726 int drm_dp_calc_pbn_mode(int clock, int bpp) 4727 { 4728 /* 4729 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on 4730 * common multiplier to render an integer PBN for all link rate/lane 4731 * counts combinations 4732 * calculate 4733 * peak_kbps = clock * bpp / 16 4734 * peak_kbps *= SSC overhead / 1000000 4735 * peak_kbps /= 8 convert to Kbytes 4736 * peak_kBps *= (64/54) / 1000 convert to PBN 4737 */ 4738 /* 4739 * TODO: Use the actual link and mode parameters to calculate 4740 * the overhead. For now it's assumed that these are 4741 * 4 link lanes, 4096 hactive pixels, which don't add any 4742 * significant data padding overhead and that there is no DSC 4743 * or FEC overhead. 4744 */ > 4745 int overhead = drm_dp_bw_overhead(4, 4096, 0, bpp, 4746 DRM_DP_BW_OVERHEAD_MST | 4747 DRM_DP_BW_OVERHEAD_SSC); 4748 4749 return DIV64_U64_ROUND_UP(mul_u32_u32(clock * bpp, 64 * overhead >> 4), 4750 1000000ULL * 8 * 54 * 1000); 4751 } 4752 EXPORT_SYMBOL(drm_dp_calc_pbn_mode); 4753 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
