Re: [PATCH] input: fix ucb1x00-ts breakage after conversion to dynamic input_dev allocation

[Nicolas Pitre <nico@cam.org>]

On Fri, 9 Dec 2005, Dmitry Torokhov wrote:

> On 12/9/05, Nicolas Pitre <nico@cam.org> wrote:
> > The bd622663192e8ebebb27dc1d9397f352a82d2495 commit broke the UCB1x00
> > touchscreen driver since the idev structure was assumed to be into the
> > ts structure, simply casting the former to the later in a couple places.
> >
> > This patch fixes those, and also cache the idev pointer between multiple
> > calls to input_report_abs() to avoid growing the compiled code
> > needlessly.
> >
> > Signed-off-by: Nicolas Pitre <nico@cam.org>
> >
> > ---
> >
> > diff --git a/drivers/mfd/ucb1x00-ts.c b/drivers/mfd/ucb1x00-ts.c
> > index a984c0e..e0794c2 100644
> > --- a/drivers/mfd/ucb1x00-ts.c
> > +++ b/drivers/mfd/ucb1x00-ts.c
> > @@ -59,16 +59,18 @@ static int adcsync;
> >
> >  static inline void ucb1x00_ts_evt_add(struct ucb1x00_ts *ts, u16 pressure, u16 x, u16 y)
> >  {
> > -       input_report_abs(ts->idev, ABS_X, x);
> > -       input_report_abs(ts->idev, ABS_Y, y);
> > -       input_report_abs(ts->idev, ABS_PRESSURE, pressure);
> > -       input_sync(ts->idev);
> > +       struct input_dev *idev = ts->idev;
> > +       input_report_abs(idev, ABS_X, x);
> > +       input_report_abs(idev, ABS_Y, y);
> > +       input_report_abs(idev, ABS_PRESSURE, pressure);
> > +       input_sync(idev);
> >  }
> >
> >  static inline void ucb1x00_ts_event_release(struct ucb1x00_ts *ts)
> >  {
> > -       input_report_abs(ts->idev, ABS_PRESSURE, 0);
> > -       input_sync(ts->idev);
> > +       struct input_dev *idev = ts->idev;
> > +       input_report_abs(idev, ABS_PRESSURE, 0);
> > +       input_sync(idev);
> >  }
> >
> 
> The changes above are not really needed.

They are, I hope, obvious enough, and they fix what I'd call a generated 
assembly regression which was introduced by said commit above.  Before 
that commit the generated assembly was (more) optimal and the those 
changes are meant to bring that state back.

> The rest is good and we
> should get it int before 2.6.15 I think.

Indeed.  Otherwise the driver simply crashes.


Nicolas