Re: [PATCH 2/2] tests/kms_fbc_crc: Fill entire target framebuffer to adds crc FIXMES

Daniel Vetter
2015-03-26T10:02:10Z

On Thu, Mar 26, 2015 at 09:35:10AM +0200, Ville Syrjälä wrote:
> On Wed, Mar 25, 2015 at 06:47:21PM -0300, Paulo Zanoni wrote:
> > 2015-03-25 17:15 GMT-03:00 Daniel Vetter <daniel.vetter@ffwll.ch>:
> > > And use the same colors for both flip and fills so that we can reuse
> > > crcs. Some details:
> > > - For the flip_and_foo tests flip twice so that we again start with
> > > the black framebuffer and hence have a real change when painting it
> > > white.
> >
> > But you don't really check the CRC after the first flip, so if it's
> > completely ignored by the display engine, we won't know. That still
> > looks like a regression from the previous code we had.
> >
> > > - The upload for the rendercopy source isn't fast, but hey I'm lazy.
> >
> > You're also changing everything form single-pixel write to full-fb
> > write, which is not necessarily a bad thing (although slower), but
> > could at least be on the changelog.
>
> The reason I riginally used very small operations was to make sure the
> hardware catches precicesly such small operations. If we just blast
> away the entire thing we can't tell if the hardware would even notice
> a small change. Although since hardware tracking was declared to be
> the evil that may not matter so much, except people still want to use
> the GTT tracking for some reason.

We're still using the gtt cpu write tracking, which is the only hw
tracking bit that works per-line-block. I guess if we see that one fail we
can add a specific testcase for the pattern, but for now I kinda trust the
hw in that regard actually. At least I haven't seen bugs like that.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation