Re: [PATCH] iio: buffer: Silence lock nesting splat

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 23 Aug 2022 10:10:45 +0200
Vincent Whitchurch <vincent.whitchurch@axis.com> wrote:

> On Sat, Aug 20, 2022 at 01:08:00PM +0200, Jonathan Cameron wrote:
> > On Fri, 19 Aug 2022 11:03:55 +0300
> > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:  
> > > On top of that, Fixes tag?  
> > It's going to be tricky to identify - the interface predates usecases that were IIO
> > drivers by a long way.  I guess introduction of first IIO driver that used
> > a callback buffer? No idea which one that was :(  
> 
> AFAICS there's only one IIO driver upstream using a callback buffer, and
> it's lmp91000, so I can point the fixes tag to the patch which added
> that.

Ah. That's handy.

> 
> By the way, note that lmp91000 actually fails to probe in mainline
> without extra patches, and it seems to have been that way for a while
> now.  I noticed this lockdep splat when working on a new driver which
> also uses a callback buffer.  I can post the fixes I used to get
> lmp91000 to probe successfully (in roadtest) separately.
That would be great.  Unfortunately drivers sometimes bit rot
without testing.

Any plans to post updated roadtest soon?  I'm keen to add more test cases
and use it to cleanup the remaining staging drivers.  Very helpful tool,
but I don't want to be developing test sets against an old version if
it's going to be costly to forward port it. No great rush though as
I've bitten off a bit more than I was aiming to in prep for plumbers so
not going to get anything significant done in IIO until mid September.

Thanks,

Jonathan