tree: https://github.com/ribalda/linux uvc-noncontiguous head: 08aff4b45dd51b3dfba18af4aa40b0fa5e2b5529 commit: 817731cae164166428258499e995dfe1ed135ad1 [4/5] TEST-ONLY: media: uvcvideo: Add statistics for measuring performance config: xtensa-allyesconfig (attached as .config) compiler: xtensa-linux-gcc (GCC) 9.3.0 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/ribalda/linux/commit/817731cae164166428258499e995dfe1e... git remote add ribalda https://github.com/ribalda/linux git fetch --no-tags ribalda uvc-noncontiguous git checkout 817731cae164166428258499e995dfe1ed135ad1 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 909 | size_t uvc_video_dump_time_stats(char *buf, size_t size, | ^~~~~~~~~~~~~~~~~~~~~~~~~ 930 | size_t uvc_video_dump_speed(char *buf, size_t size, const char *pfx, u64 bytes, | ^~~~~~~~~~~~~~~~~~~~ vim +/uvc_video_dump_time_stats +909 drivers/media/usb/uvc/uvc_video.c 908 910 struct uvc_stats_time *stat, const char *pfx) 911 { 912 unsigned int avg = 0; 913 unsigned int std = 0; 914 915 if (stat->qty) { 916 avg = div_u64(stat->duration, stat->qty); 917 std = int_sqrt64(div_u64(stat->duration2, stat->qty) - 918 avg * avg); 919 } 920 921 /* Stat durations are in nanoseconds, we present in micro-seconds */ 922 return scnprintf( 923 buf, size, 924 "%s: %llu/%u uS/qty: %u.%03u avg %u.%03u std %u.%03u min %u.%03u max (uS)\n", 925 pfx, div_u64(stat->duration, 1000), stat->qty, avg / 1000, 926 avg % 1000, std / 1000, std % 1000, stat->min / 1000, 927 stat->min % 1000, stat->max / 1000, stat->max % 1000); 928 } 929 931 u64 milliseconds) 932 { 933 unsigned int rate = 0; 934 bool gbit = false; 935 936 if (milliseconds) 937 rate = div_u64(bytes * 8, milliseconds); 938 939 if (rate >= 1000000) { 940 gbit = true; 941 rate /= 1000; 942 } 943 944 /* 945 * bits/milliseconds == kilobits/seconds, 946 * presented here as Mbits/s (or Gbit/s) with 3 decimal places 947 */ 948 return scnprintf(buf, size, "%s: %d.%03d %sbits/s\n", pfx, rate / 1000, 949 rate % 1000, gbit ? "G" : "M"); 950 } 951 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org