Re: [PATCH v2 4/5] iio: adc: ti-adc161s626: log buffer setup failure in probe

[Jonathan Cameron]

On Wed, 24 Jun 2026 14:26:52 +0300
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> wrote:

> On Wed, Jun 24, 2026 at 03:43:44PM +0530, Prashant Rahul wrote:
> > On Wed Jun 24, 2026 at 1:06 AM IST, Jonathan Cameron wrote:  
> > > Why this particular one but not the devm_iio_device_register() below it?
> > > Both pretty much only fail on driver bugs.  Or out of memory for
> > > which dev_err_probe() doesn't print anything anyway (on basis that
> > > is normally pretty noisy).  
> > 
> > My apologies, I wasnt aware that dev_err_probe simply ignores `-ENOMEM`.
> > Looking at drivers/base/core.c:5096, it is pretty evident that it does.
> > 
> > My goal with the patch series was to change dev_err into dev_err_probe,
> > as my understanding of dev_err_probe was that it's a specialization of
> > dev_err for probe contexts.  
> 
> Jonathan, actually the triggered buffer setup might return not -ENOMEM error
> code for the surprise. After all this series does add not a dead code, but
> a quite rare to be used one.
> 
> https://elixir.bootlin.com/linux/v7.1.1/source/drivers/iio/buffer/industrialio-triggered-buffer.c#L57
> 
> 

Agreed and I'm not even sure why that is there (lost to the mists of time
/ my failing memory ;)  However I think it's an obvious driver bug case
that should be trivial to see in basic tests so to me it's marginal on
whether a print on these is useful.

Maybe given that one is so rare we should just add a print in the core?
I'm not particularly keen on mass patches to print errors from the core
code but this one is perhaps a reasonable trade off vs series like this
one adding prints to drivers for something we don't think realistically
ever happens.

Jonathan