Re: [PATCH] iio: core: Avoid BUG() on invalid clock types

[Rishab M]

Hi Jonathan, Andy, and Joshua,

Thank you for the feedback and for sharing the documentation reference.
I will incorporate the reference to the documentation in the v2 commit
message and update the default cases to use WARN_ON_ONCE(1) as
Jonathan suggested.

I will send the v2 patch shortly.

Best regards,
Rishab


On Mon, Aug 24, 2026 at 8:25 AM Andy Shevchenko
<andriy.shevchenko@xxxxxxxxx> wrote:
>
> On Mon, Aug 24, 2026 at 05:06:24PM +0200, Joshua Crofts wrote:
> > On Mon, 24 Aug 2026 at 16:48, Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxx> wrote:
> > > On Mon, Aug 24, 2026 at 12:05:03PM +0200, Joshua Crofts wrote:
> > > > On Mon, 24 Aug 2026 12:55:47 +0300
> > > > Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> wrote:
> > > > > On Sun, Aug 23, 2026 at 10:25:02PM +0000, Rishab Madhugiri wrote:
> > > > > > Replace deprecated use of BUG() in default switch cases of
> > > > > > iio_get_time_ns() and current_timestamp_clock_show() with
> > > > > > WARN_ONCE() and return correct fallback or error codes.
> > > > >
> > > > > Why?!
> > > >
> > > > Because BUG() and BUG_ON() shouldn't be used anymore, no? Linus himself
> > > > said that he hates the macros.
> > >
> > > Why? Please, study the case. As for the above change, there are two questions
> > > (at least):
> > > - Why BUG() is deprecated? Where is it stated?
> >
> > https://docs.kernel.org/process/deprecated.html?hl=en-GB#bug-and-bug-on
>
> Thanks for sharing! So, this is a missing point in the commit message.
>
> > > - What will WARN*() gain us here? (Note some specific kernel command line
> > >   parameter that may convert WARN to BUG)
> >
> > As Jonathan mentioned earlier, the original BUG() was there to prevent the
> > compiler from complaining that all possible values weren't handled. So BUG()
> > or WARN*() here is a placeholder. Just removing the BUG() call should be
> > valid since it's impossible to hit(?)
>
> Yeah, I was participated in several cases where the compiler made something
> strange when BUG() was absent (basically no reachable point which BUG()
> represents). Do we have no issues (anymore?) with the compiler with WARN*()?
>
> --
> With Best Regards,
> Andy Shevchenko
>
>