[igt-dev] [PATCH i-g-t] tests/kms_flip: Fix comparison of unsigned integers

[Chris Wilson]

Quoting Petri Latvala (2019-03-05 12:55:01)
> On Thu, Feb 07, 2019 at 04:02:12PM +0200, Ville Syrjälä wrote:
> > On Thu, Feb 07, 2019 at 03:36:52PM +0200, Petri Latvala wrote:
> > > Difference of unsigned ints is unsigned int, and therefore always
> > > larger than zero.
> > > 
> > > Signed-off-by: Petri Latvala <petri.latvala at intel.com>
> > > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > ---
> > >  tests/kms_flip.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/tests/kms_flip.c b/tests/kms_flip.c
> > > index 798fc4e8..96f4a2f7 100755
> > > --- a/tests/kms_flip.c
> > > +++ b/tests/kms_flip.c
> > > @@ -502,7 +502,7 @@ static void check_state(const struct test_output *o, const struct event_state *e
> > >     if (o->flags & TEST_TS_CONT) {
> > >             /* Ignore seq_step here since vblank waits time out immediately
> > >              * when we kill the crtc. */
> > > -           igt_assert_f(es->current_seq - es->last_seq >= 0,
> > > +           igt_assert_f(es->current_seq >= es->last_seq,
> > 
> > That won't handle wraparound.
> 
> Are you referring to something other than the checked overflow? Or in
> other words, are you objecting to this patch?

/* a is later than b */
static bool seqno_later(u32 a, u32 b) { return (s32)(a - b) >= 0; }
-Chris