From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>,
Daniel Vetter <daniel@ffwll.ch>,
intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH igt] igt/kms_flip: Calibrate timestamp errors
Date: Wed, 26 Oct 2016 08:18:13 +0200 [thread overview]
Message-ID: <20161026061813.4oathxxsfzf3nuzy@phenom.ffwll.local> (raw)
In-Reply-To: <20161024093834.GD19601@nuc-i3427.alporthouse.com>
On Mon, Oct 24, 2016 at 10:38:34AM +0100, Chris Wilson wrote:
> On Mon, Oct 24, 2016 at 11:14:31AM +0200, Daniel Vetter wrote:
> > On Mon, Oct 24, 2016 at 09:54:52AM +0100, Chris Wilson wrote:
> > Also with this patch we should be able to throw out the hacks for tv-out.
> > I only added those because the reported mode-timings are massively off
> > (due to the magic tv scaler thing) from the real timestamps we receive.
> > Auto-detecting this is much better.
>
> Not quite just yet, we need to split the timing tests into a subgroup
> with a subtest per output so that we can skip one without skipping the
> others. At the moment, this check makes it bail out on my ctg/ilk who
> have a difference of about 50us between measured and expected vblank
> interval on LVDS (which is nigh on impossible given our confidence in the
> measurement, i.e. about 7 sigma).
Hm, should we be a bit more sloppy in our acceptance? Iirc Ville has made
changes to make it a bit more strict a while ago, and way, way back this
stuff worked on my ctg. Haven't fired it up in a while ;-)
> > And another issue: Failing to match the reported mode timings is a driver
> > bug.
>
> Not quite, remember we override the user for fixed mode panels. But yes,
> piglit also has a similar expectation that the dotclock we report (via
> GetMscRate) in someway corresponds to actual vblank interval.
Yeah, I hope that DRRS would fix that, at least on newer stuff. At least I
proposed just using the matching dotclock for manual DRRS (mostly to
perfectly match with the refresh rate of a video). Didn't yet happen :(
But at least for the default mode we should try real hard to match.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2016-10-26 6:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-24 8:54 [PATCH igt] igt/kms_flip: Calibrate timestamp errors Chris Wilson
2016-10-24 9:14 ` Daniel Vetter
2016-10-24 9:38 ` Chris Wilson
2016-10-26 6:18 ` Daniel Vetter [this message]
2016-10-26 9:10 ` Chris Wilson
2016-10-26 9:17 ` Ville Syrjälä
2016-10-27 6:43 ` Daniel Vetter
2016-10-27 10:13 ` Ville Syrjälä
2016-10-27 10:29 ` Chris Wilson
2016-10-27 11:41 ` Ville Syrjälä
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