reproduce (this is a W=1 build):
        git remote add johan-usb-serial https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial.git
        git fetch johan-usb-serial usb-next
        git checkout johan-usb-serial/usb-next
        b4 shazam https://lore.kernel.org/r/20260324124619.843-1-charlesyeh522@gmail.com

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/usb/serial/