Re: [PATCH 2.6] input: do not suppress 0 value relative events

[Vojtech Pavlik <vojtech@suse.cz>]

On Sat, Oct 04, 2003 at 02:22:57AM -0500, Dmitry Torokhov wrote:
>   Input: input susbsystem should not drop 0 value relative events,
>          otherwise unsuspecting programs will loose transitions from
>          non-zero to 0 deltas. We should not require userland authors
>          to consult with kernel implementation details all the time,
>          but follow the principle of least surprise and report
>          everything.

Certain devices will then generate an endless stream of zero-movement
relative events, which is not good.

Because 'relative' means that there is no movement when there is no
event, where exactly lies the problem? What application has a problem
with this? Many mice don't ever report zero values, so that application
will probably not work even without the (value==0) check ...

>  input.c |    2 +-
>  1 files changed, 1 insertion(+), 1 deletion(-)
> 
> ===================================================================
> 
> diff -Nru a/drivers/input/input.c b/drivers/input/input.c
> --- a/drivers/input/input.c	Sat Oct  4 02:20:18 2003
> +++ b/drivers/input/input.c	Sat Oct  4 02:20:18 2003
> @@ -134,7 +134,7 @@
>  
>  		case EV_REL:
>  
> -			if (code > REL_MAX || !test_bit(code, dev->relbit) || (value == 0))
> +			if (code > REL_MAX || !test_bit(code, dev->relbit))
>  				return;
>  
>  			break;

-- 
Vojtech Pavlik
SuSE Labs, SuSE CR