tree:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
head:   630a159a0bf35fdc944c8e9633ed5aef0a6834db
commit: ab2b29e64e05f2d92dc4a584de7818bc9a1eea4c [6/8] video: fbdev: s3c-fb: Fix kernel-doc and set but not used warnings
config: riscv-randconfig-r022-20201217 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project cee1e7d14f4628d6174b33640d502bff3b54ae45)
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
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        git remote add drm-drm-misc git://anongit.freedesktop.org/drm/drm-misc
        git fetch --no-tags drm-drm-misc drm-misc-next
        git checkout ab2b29e64e05f2d92dc4a584de7818bc9a1eea4c
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

Note: the drm-drm-misc/drm-misc-next HEAD a1b766d1b3646b5ef90f0fa7b42fd99bbd166766 builds fine.
      It only hurts bisectibility.

All errors (new ones prefixed by >>):

   /tmp/lm95234-009664.s: Assembler messages:
>> /tmp/lm95234-009664.s:278: Error: unrecognized opcode `zext.b a2,a0'
>> /tmp/lm95234-009664.s:672: Error: unrecognized opcode `zext.b a1,a0'
   /tmp/lm95234-009664.s:679: Error: unrecognized opcode `zext.b a1,a0'
   /tmp/lm95234-009664.s:700: Error: unrecognized opcode `zext.b a1,a0'
   /tmp/lm95234-009664.s:707: Error: unrecognized opcode `zext.b a1,a0'
   /tmp/lm95234-009664.s:807: Error: unrecognized opcode `zext.b a1,a0'
   /tmp/lm95234-009664.s:828: Error: unrecognized opcode `zext.b a1,a0'
   /tmp/lm95234-009664.s:852: Error: unrecognized opcode `zext.b a1,a0'
>> /tmp/lm95234-009664.s:1243: Error: unrecognized opcode `zext.b a2,a1'
>> /tmp/lm95234-009664.s:1426: Error: unrecognized opcode `zext.b a1,a1'
   /tmp/lm95234-009664.s:1635: Error: unrecognized opcode `zext.b a1,a1'
   /tmp/lm95234-009664.s:2110: Error: unrecognized opcode `zext.b a1,a1'
>> /tmp/lm95234-009664.s:2299: Error: unrecognized opcode `zext.b s1,s1'
   clang-12: error: assembler command failed with exit code 1 (use -v to see invocation)

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org