Re: [PATCH i-g-t] tests/kms_frontbuffer_tracking: increase FBC wait timeout to 5s

Lofstedt, Marta
2017-08-08T11:14:42Z

> -----Original Message-----
> From: Zanoni, Paulo R
> Sent: Monday, August 7, 2017 5:54 PM
> To: Lofstedt, Marta <marta.lofstedt@intel.com>; intel-
> gfx@lists.freedesktop.org
> Cc: Latvala, Petri <petri.latvala@intel.com>
> Subject: Re: [PATCH i-g-t] tests/kms_frontbuffer_tracking: increase FBC wait
> timeout to 5s
>
> Em Seg, 2017-08-07 às 06:51 +0000, Lofstedt, Marta escreveu:
> > > -----Original Message-----
> > > From: Zanoni, Paulo R
> > > Sent: Friday, August 4, 2017 9:56 PM
> > > To: Lofstedt, Marta <marta.lofstedt@intel.com>; intel-
> > > gfx@lists.freedesktop.org
> > > Cc: Latvala, Petri <petri.latvala@intel.com>
> > > Subject: Re: [PATCH i-g-t] tests/kms_frontbuffer_tracking: increase
> > > FBC wait timeout to 5s
> > >
> > > Em Sex, 2017-08-04 às 09:47 +0000, Lofstedt, Marta escreveu:
> > > > +Paolo
> > > >
> > > > > -----Original Message-----
> > > > > From: Lofstedt, Marta
> > > > > Sent: Wednesday, June 28, 2017 2:17 PM
> > > > > To: intel-gfx@lists.freedesktop.org
> > > > > Cc: Latvala, Petri <petri.latvala@intel.com>; Lofstedt, Marta
> > > > > <marta.lofstedt@intel.com>
> > > > > Subject: [PATCH i-g-t] tests/kms_frontbuffer_tracking: increase
> > > > > FBC wait timeout to 5s
> > > > >
> > > > > The subtests: igt@kms_frontbuffer_tracking@fbc-*draw*
> > > > > has non-consistent results, pending between fail and pass.
> > > > > The fails are always due to "FBC disabled".
> > > > > With this increase in timeout the flip-flop behavior is no
> > > > > longer reproducible.
> > >
> > > This is a partial revert of:
> > >
> > > 64590c7b768dc8d8dd962f812d5ff5a39e7e8b54
> > >     kms_frontbuffer_tracking: reduce the FBC wait timeout to 2s
> > >
> > > (but there's no need to make it a full revert if you don't need)
> > >
> > > It would be nice to investigate why we're needing 5 seconds instead
> > > of
> > > 2 now, the document it in the commit message. Also document that
> > > this is a partial revert.
> >
> > Paulo, do you have data backing up that 2 seconds was ever OK, I fail
> > ~1/10 on various fbc subtests.
>
> All the data I have is the commit message of 64590c7b and the testing I did. I
> would imagine something changed in the upstream tree since then, causing
> this to need a longer timeout, that's why I suggested investigating.
>
If I run current IGT with Kernel 4.2.0, which was released 30 august 2015, that should be around the time when the 64590c7b was done, all kms_frontbuffer_tracking tests fail. If I reset IGT to 64590c7b half of the flip-flopping tests consistently fail the rest consistently pass over 10 runs. If I run IGT@64590c7b on 4.13-rc3+ all kms_fronbuffer_tracking fail. So, indeed some of these tests appear to actually have passed 2 years ago, but it also seem that both the tests and the i915 have change a lot during 2 years.
Anyways, I will do some timing analyze to investigate what is really going on here.

/Marta

> >
> > /Marta
> > >
> > > Acked-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > >
> >
> > Thanks,
> >
> > > > >
> > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101623
> > > > > Signed-off-by: Marta Lofstedt <marta.lofstedt@intel.com>
> > > > > ---
> > > > >  tests/kms_frontbuffer_tracking.c | 2 +-
> > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/tests/kms_frontbuffer_tracking.c
> > > > > b/tests/kms_frontbuffer_tracking.c
> > > > > index c24e4a81..8bec5d5a 100644
> > > > > --- a/tests/kms_frontbuffer_tracking.c
> > > > > +++ b/tests/kms_frontbuffer_tracking.c
> > > > > @@ -923,7 +923,7 @@ static bool fbc_stride_not_supported(void)
> > > > >
> > > > >  static bool fbc_wait_until_enabled(void)  {
> > > > > - return igt_wait(fbc_is_enabled(), 2000, 1);
> > > > > + return igt_wait(fbc_is_enabled(), 5000, 1);
> > > > >  }
> > > > >
> > > > >  static bool psr_wait_until_enabled(void)
> > > > > --
> > > > > 2.11.0
> > > >
> > > >