Re: drivers/char/hw_random/npcm-rng.c:166:34: warning: unused variable 'rng_dt_id'

From: Nathan Chancellor
Date: Fri Jun 26 2020 - 02:52:54 EST


On Fri, Jun 26, 2020 at 04:42:25PM +1000, Herbert Xu wrote:
> On Tue, Jun 23, 2020 at 09:58:39PM +0800, kernel test robot wrote:
> >
> > >> drivers/char/hw_random/npcm-rng.c:166:34: warning: unused variable 'rng_dt_id' [-Wunused-const-variable]
> > static const struct of_device_id rng_dt_id[] = {
> > ^
> > 1 warning generated.
>
> The kernel is supposed to be built with -Wno-unused-const-variable,
> so I guess this is a deficiency in clang.
>
> Cheers,
> --
> Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
>

No deficiency in clang, it's a W=1 build, which explicitly enables
-Wunused-const-variable per scripts/Kbuild.extrawarn. The 0day team
decided to enable W=1 for all build tests, hence the comment in the
reproduce notes. A thread with discussion:

https://lore.kernel.org/lkml/202005200123.gFjGzJEH%25lkp@xxxxxxxxx/

Cheers,
Nathan