reproduce:
        git remote add pci https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git
        git fetch pci next
        git checkout pci/next
        b4 shazam https://lore.kernel.org/r/1767929389-143957-3-git-send-email-shawn.lin@rock-chips.com
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs