Re: [PATCH 2/9] input: goodix: fix variable length array warning

[Antonio Ospite <ao2@ao2.it>]

On Thu, 28 May 2015 15:47:38 +0300
Irina Tirdea <irina.tirdea@intel.com> wrote:

> Fix sparse warning:
> drivers/input/touchscreen/goodix.c:182:26: warning:
> Variable length array is used.
> 
> Replace the variable length array with fixed length.
> 
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> ---
>  drivers/input/touchscreen/goodix.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> index c2e785c..dac1b3c 100644
> --- a/drivers/input/touchscreen/goodix.c
> +++ b/drivers/input/touchscreen/goodix.c
> @@ -147,7 +147,7 @@ static void goodix_ts_report_touch(struct goodix_ts_data *ts, u8 *coor_data)
>   */
>  static void goodix_process_events(struct goodix_ts_data *ts)
>  {
> -	u8  point_data[1 + GOODIX_CONTACT_SIZE * ts->max_touch_num];
> +	u8  point_data[1 + GOODIX_CONTACT_SIZE * GOODIX_MAX_CONTACTS];

Hi,

this fixes the warning from sparse, but also changes the semantics of
the code: ts->max_touch_num is less that GOODIX_MAX_CONTACTS for 5
touches devices and in this case we'll end up using more memory than is
necessary.

Thanks,
   Antonio

>  	int touch_num;
>  	int i;
>  
> -- 
> 1.9.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-input" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Antonio Ospite
http://ao2.it

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?