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