Hi Vinod, kernel test robot noticed the following build warnings: [auto build test WARNING on drm-tip/drm-tip] url: https://github.com/intel-lab-lkp/linux/commits/Vinod-Govindapillai/drm-i915-update-the-QGV-point-frequency-calculations/20230426-042322 base: git://anongit.freedesktop.org/drm/drm-tip drm-tip patch link: https://lore.kernel.org/r/20230425202056.1143994-5-vinod.govindapillai%40intel.com patch subject: [PATCH v1 4/7] drm/i915: modify max_bw to return index to intel_bw_info config: i386-randconfig-a004 (https://download.01.org/0day-ci/archive/20230426/202304260652.5QRXxuHt-lkp@xxxxxxxxx/config) compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/5f1409d5142339d50e5018b0908f9e232ca1f738 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Vinod-Govindapillai/drm-i915-update-the-QGV-point-frequency-calculations/20230426-042322 git checkout 5f1409d5142339d50e5018b0908f9e232ca1f738 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/gpu/drm/i915/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Link: https://lore.kernel.org/oe-kbuild-all/202304260652.5QRXxuHt-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> drivers/gpu/drm/i915/display/intel_bw.c:833:7: warning: variable 'idx' is uninitialized when used here [-Wuninitialized] if (idx > ARRAY_SIZE(i915->display.bw.max)) ^~~ drivers/gpu/drm/i915/display/intel_bw.c:825:19: note: initialize the variable 'idx' to silence this warning unsigned int idx; ^ = 0 1 warning generated. vim +/idx +833 drivers/gpu/drm/i915/display/intel_bw.c 804 805 static int icl_find_qgv_points(struct drm_i915_private *i915, 806 unsigned int data_rate, 807 unsigned int num_active_planes, 808 const struct intel_bw_state *old_bw_state, 809 struct intel_bw_state *new_bw_state) 810 { 811 unsigned int max_bw_point = 0; 812 unsigned int max_bw = 0; 813 unsigned int num_psf_gv_points = i915->display.bw.max[0].num_psf_gv_points; 814 unsigned int num_qgv_points = i915->display.bw.max[0].num_qgv_points; 815 u16 psf_points = 0; 816 u16 qgv_points = 0; 817 int i; 818 int ret; 819 820 ret = intel_atomic_lock_global_state(&new_bw_state->base); 821 if (ret) 822 return ret; 823 824 for (i = 0; i < num_qgv_points; i++) { 825 unsigned int idx; 826 unsigned int max_data_rate; 827 828 if (DISPLAY_VER(i915) > 11) 829 tgl_max_bw_index(i915, num_active_planes, i); 830 else 831 icl_max_bw_index(i915, num_active_planes, i); 832 > 833 if (idx > ARRAY_SIZE(i915->display.bw.max)) 834 continue; 835 836 max_data_rate = i915->display.bw.max[idx].deratedbw[i]; 837 838 /* 839 * We need to know which qgv point gives us 840 * maximum bandwidth in order to disable SAGV 841 * if we find that we exceed SAGV block time 842 * with watermarks. By that moment we already 843 * have those, as it is calculated earlier in 844 * intel_atomic_check, 845 */ 846 if (max_data_rate > max_bw) { 847 max_bw_point = i; 848 max_bw = max_data_rate; 849 } 850 if (max_data_rate >= data_rate) 851 qgv_points |= BIT(i); 852 853 drm_dbg_kms(&i915->drm, "QGV point %d: max bw %d required %d\n", 854 i, max_data_rate, data_rate); 855 } 856 857 for (i = 0; i < num_psf_gv_points; i++) { 858 unsigned int max_data_rate = adl_psf_bw(i915, i); 859 860 if (max_data_rate >= data_rate) 861 psf_points |= BIT(i); 862 863 drm_dbg_kms(&i915->drm, "PSF GV point %d: max bw %d" 864 " required %d\n", 865 i, max_data_rate, data_rate); 866 } 867 868 /* 869 * BSpec states that we always should have at least one allowed point 870 * left, so if we couldn't - simply reject the configuration for obvious 871 * reasons. 872 */ 873 if (qgv_points == 0) { 874 drm_dbg_kms(&i915->drm, "No QGV points provide sufficient memory" 875 " bandwidth %d for display configuration(%d active planes).\n", 876 data_rate, num_active_planes); 877 return -EINVAL; 878 } 879 880 if (num_psf_gv_points > 0 && psf_points == 0) { 881 drm_dbg_kms(&i915->drm, "No PSF GV points provide sufficient memory" 882 " bandwidth %d for display configuration(%d active planes).\n", 883 data_rate, num_active_planes); 884 return -EINVAL; 885 } 886 887 /* 888 * Leave only single point with highest bandwidth, if 889 * we can't enable SAGV due to the increased memory latency it may 890 * cause. 891 */ 892 if (!intel_can_enable_sagv(i915, new_bw_state)) { 893 qgv_points = BIT(max_bw_point); 894 drm_dbg_kms(&i915->drm, "No SAGV, using single QGV point %d\n", 895 max_bw_point); 896 } 897 898 /* 899 * We store the ones which need to be masked as that is what PCode 900 * actually accepts as a parameter. 901 */ 902 new_bw_state->qgv_points_mask = 903 ~(ICL_PCODE_REQ_QGV_PT(qgv_points) | 904 ADLS_PCODE_REQ_PSF_PT(psf_points)) & 905 icl_qgv_points_mask(i915); 906 907 /* 908 * If the actual mask had changed we need to make sure that 909 * the commits are serialized(in case this is a nomodeset, nonblocking) 910 */ 911 if (new_bw_state->qgv_points_mask != old_bw_state->qgv_points_mask) { 912 ret = intel_atomic_serialize_global_state(&new_bw_state->base); 913 if (ret) 914 return ret; 915 } 916 917 return 0; 918 } 919 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests
