Re: [PATCH] fix n900 dts file to work around 4.1 touchscreen regression on n900

Maxime Ripard
2015-06-01T10:00:23Z

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On Fri, May 29, 2015 at 10:34:56PM +0200, Pavel Machek wrote:
> Hi!
>
> > > > single DT, you don't even use that property in your driver, and now
> > > > that you realise you meant something else, you want the code that
> > >
> > > not Pali, Sebastian.
> > >
> > > > actually parse the *right* property and does the right thing, that all
> > > > other DT agree (and depend on) to be reverted?
> > >
> > > We shouldn't revert, that I agree. But both properties should be parsed.
> >
> > No. If the property is wrong, and nobody parsed it, I do not see any reason to
> > start now.
>
> Agreed.
>
> But that's not what I'm asking. See a changelog of
> 3eea8b5d68c801fec788b411582b803463834752 and compare it with what it
> actually does.
>
> It is buggy. If fuzz is specified but maximum is not, it overwites
> maximum with zero.

If maximum is not set, you'll have other issues anyway. But it really
boils down on what the default behaviour should be.

> Plus it introduces new failure "if (!test_bit(axis, dev->absbit))".

It's not a new failure, it's testing against stupid code.

If an axis is setup in the DT but not registered in the driver,
something is wrong, most probably the DT.

> Plus it fails to distinguish between "value not specified in the dt"
> and "zero is specified in the dt".

Again, default behaviour.

> The 3eea8b5d68c801fec788b411582b803463834752 is just bad.

You were very welcome to review this patch at the time and/or suggest
a fix that pleases everyone.

Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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