Hi Arnd,

On Fri, Jan 29, 2016 at 12:07 AM, Arnd Bergmann [off-list ref] wrote:

The other related issue is the DEBUG_UART_{VIRT,PHYS} setting,
where there is no safe platform-specific default. I have two
ideas for working around that, maybe one of them sounds ok to
you:

a) find a way to warn and/or disable DEBUG_LL when no address
   is set, rather than failing the build

b) add 'default 0 if COMPILE_TEST' to make it harder to get this
   wrong by accident (hopefully nobody tries to run a COMPILE_TEST
   kernel). Also maybe add a #warning if DEBUG_UART_VIRT is

Make sure to add it at the end of the list, so enabling COMPILE_TEST in a
working .config should give another working .config.

Perhaps you can use 0xdeadbeef instead of 0, and add

    #if DEBUG_UART_PHYS == 0xdeadbeed
    #warning Broken value of DEBUG_UART_PHYS.
    #endif

somewhere?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds