[PATCH] gpio/generic: initialize the shadow of direction register

Lothar Waßmann LW at KARO-electronics.de
Wed May 16 09:33:26 EDT 2012


Hi,

Shawn Guo writes:
> On Wed, May 16, 2012 at 02:48:23PM +0200, Lothar Waßmann wrote:
> > But you are changing the behaviour of existing software that
> > apparently did not suffer from this problem.
> 
> It's exactly the reason why you chose to fix the problem in gpio-mxc
> instead of gpio-generic, right?  You thought other gpio-generic users
> like gpio-mxs does not suffer from this problem.  Sadly, it's not the
> case.
> 
> The updated patch simply corrects behaviour of gpio-generic for all
> the users.
> 
> > You should make sure that
> > the fix for your problem is not causing new problems for other users!
> > 
> I'm not fixing a gpio-mxs problem but a gpio-generic one.  Can you help
>
Yes, I know. And that's exaclty why you should make sure that you
don't break other platforms by fixing yours!

> me understand what the new problems could possibly be introduced for
> other gpio-generic users by the changes? 
> 
Another platform using might be working just _because_ of the "broken"
behaviour. By fixing that brokenness for your driver you may break
that other platform.


Lothar Waßmann
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