Re: [PATCH] Input: bcm5974.c initialize raw_w, raw_x and raw_y before it get used

[Henrik Rydberg <rydberg@bitmath.org>]

Jaswinder Singh Rajput wrote:
> raw_w, raw_x and raw_y is used uninitialized for !raw_n

Thanks for the heads up, but actually not, since !raw_n also implies
!(ptest > PRESSURE_LOW).

> This also fixed these compilation warnings :
> 
>  CC [M]  drivers/input/mouse/bcm5974.o
> drivers/input/mouse/bcm5974.c: In function ‘report_tp_state’:
> drivers/input/mouse/bcm5974.c:319: warning: ‘raw_y’ may be used uninitialized in this function
> drivers/input/mouse/bcm5974.c:319: warning: ‘raw_x’ may be used uninitialized in this function
> drivers/input/mouse/bcm5974.c:319: warning: ‘raw_w’ may be used uninitialized in this function
> 
> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
> ---
>  drivers/input/mouse/bcm5974.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
> index 2d8fc0b..171f345 100644
> --- a/drivers/input/mouse/bcm5974.c
> +++ b/drivers/input/mouse/bcm5974.c
> @@ -345,7 +345,8 @@ static int report_tp_state(struct bcm5974 *dev, int size)
>  		/* set the integrated button if applicable */
>  		if (c->tp_type == TYPE2)
>  			ibt = raw2int(dev->tp_data[BUTTON_TYPE2]);
> -	}
> +	} else
> +		raw_w = raw_x = raw_y = 0;
>  
>  	/* while tracking finger still valid, count all fingers */
>  	if (ptest > PRESSURE_LOW && origin) {

I would prefer treating raw_p on the same footing here, completing the set of
non-obviously initialized variables. It might also make sense to utilize the
same initialization technique already used in the code, thus:

diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
index 2d8fc0b..2f85876 100644
--- a/drivers/input/mouse/bcm5974.c
+++ b/drivers/input/mouse/bcm5974.c
@@ -316,7 +316,7 @@ static int report_tp_state(struct bcm5974 *dev, int size)
 	const struct bcm5974_config *c = &dev->cfg;
 	const struct tp_finger *f;
 	struct input_dev *input = dev->input;
-	int raw_p, raw_w, raw_x, raw_y, raw_n;
+	int raw_p = 0, raw_w = 0, raw_x = 0, raw_y = 0, raw_n;
 	int ptest = 0, origin = 0, ibt = 0, nmin = 0, nmax = 0;
 	int abs_p = 0, abs_w = 0, abs_x = 0, abs_y = 0;


I wonder how many cpu cycles in the world are spent making compilers happy.

Cheers,
Henrik
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