[alsa-devel] ASoC: rsnd: fix sound route path when using SRC6/SRC9

[Geert Uytterhoeven]

Hi Morimoto-san,

On Wed, May 17, 2017 at 9:38 AM, Kuninori Morimoto
<kuninori.morimoto.gx at renesas.com> wrote:
>> > Hmm....
>> > I tried random code/compile, but gcc behavior seems strange.
>> > Fore example if I removed next line, this warning disappeard
>> >
>> > -               data = path[rsnd_mod_id(src)] |
>> > -                       cmd_case[rsnd_mod_id(src)] << 16;
>> > +               data = path[rsnd_mod_id(src)];
>> >
>> > Is this related to this ?
>> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59124
>>
>> Perhaps.
>>
>> I guess the main question is: can src be NULL here?
>> If yes, rsnd_mod_id(src) will be -1.
>
> No. cmd itself will not be used if src was NULL on this HW.

But gcc cannot know that, as the function is called through a function
pointer from another source file.

> But, yes, it seems gcc is checking -1 value here.
> It is OK, but why it warns only here ??

Yes, I'm also wondering why we see the warning only here.
I guess we should be lucky that we get it at least in one place ;-)

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