Re: [PATCH] iio: inkern: fix channel read regression

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 3 Jun 2024 09:24:38 +0200
Johan Hovold <johan@kernel.org> wrote:

> Hi Jonathan,
> 
> On Sat, Jun 01, 2024 at 02:21:47PM +0100, Jonathan Cameron wrote:
> > On Thu, 30 May 2024 09:44:16 +0200
> > Johan Hovold <johan+linaro@kernel.org> wrote:
> >   
> > > A recent "cleanup" broke IIO channel read outs and thereby thermal
> > > mitigation on the Lenovo ThinkPad X13s by returning zero instead of the
> > > expected IIO value type in iio_read_channel_processed_scale():
> > > 
> > > 	thermal thermal_zone12: failed to read out thermal zone (-22)
> > > 
> > > Fixes: 3092bde731ca ("iio: inkern: move to the cleanup.h magic")
> > > Cc: Nuno Sa <nuno.sa@analog.com>
> > > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>  
> 
> > In meantime, Nuno please take another look at these and see if
> > we have additional problem cases like this.  Given the patch
> > queue I have and a busy few days it will be a while before I
> > get to it but I'll try and take a close look soon as well.  
> 
> Please consider getting this one into mainline as soon as possible as it
> breaks thermal mitigation, which can cause literal skin burns, on all
> Qualcomm platforms (and probably other platforms too).

I'll queue this fix and we can follow with any others that surface
from reviews.

Need it to sit in linux-next for a day or two before a pull request though
as I've just pushed some other fixes out that needs some build coverage.

> 
> > Longer term, in my view the readability and chance of bugs
> > is reduced, but churn always introduces the possibility of
> > issues like this in the short term :(  
> 
> I just worry about some of the cleanup.h conversion I've seen where
> inexperienced developers potentially break tested and reviewed code for
> something which is often not very readable and for very little gain.
> 

Fair comment. There have been some 'interesting' patches.
On the plus side this one highlighted that our docs are wrong.

Applied to the fixes-togreg branch of iio.git

Jonathan


> Johan