[Mesa-dev] [PATCH mesa] meson: add missing tegra vdpau driver

[Dylan Baker]

Quoting Thierry Reding (2018-12-18 14:19:32)
> On Tue, Dec 18, 2018 at 11:34:31AM -0800, Dylan Baker wrote:
> > Quoting Eric Engestrom (2018-12-18 09:43:18)
> > > 
> > > 
> > > On December 18, 2018 5:36:19 PM UTC, Dylan Baker <dylan at pnwbakers.com> wrote:
> > > > Quoting Ilia Mirkin (2018-12-06 09:39:25)
> > > > > On Thu, Dec 6, 2018 at 12:17 PM Eric Engestrom
> > > > <eric.engestrom at intel.com> wrote:
> > > > > >
> > > > > > On Thursday, 2018-12-06 12:07:06 -0500, Ilia Mirkin wrote:
> > > > > > > Under what circumstances would tegra have a vdpau
> > > > implementation?
> > > > > >
> > > > > > I don't know about that, but this patch brings meson on par with
> > > > > > autotools. Are you saying autotools was wrong and it should be
> > > > removed
> > > > > > there instead?
> > > > > >
> > > > > > FtR, src/gallium/targets/vdpau/Makefile.am includes
> > > > > > src/gallium/drivers/tegra/Automake.inc which adds tegra to the
> > > > > > TARGET_DRIVERS, which in turn produces libvdpau_tegra.so
> > > > > >
> > > > > > If this was wrong, then that include on line 60 of
> > > > > > src/gallium/targets/vdpau/Makefile.am should be removed.
> > > > > >
> > > > > > This line was added by Thierry Reding (cc'ed) when he first
> > > > introduced
> > > > > > tegra support in 1755f608f5201e0a23f00 "tegra: Initial support".
> > > > > 
> > > > > I'd like to hear tagr opine on this, but AFAIK tegra is a
> > > > > renderonly-style driver, which uses nouveau as its actual rendering
> > > > > backend. While nouveau does support VDPAU, the decoding engines are
> > > > > not available as part of the GPU device on Tegra platforms. They
> > > > still
> > > > > have decoders, they're just separate platform devices (which I
> > > > suspect
> > > > > operate very similarly to their desktop GPU counterparts, but that's
> > > > a
> > > > > separate matter).
> > > > > 
> > > > >   -ilia
> > > > 
> > > > Ping?
> > > 
> > > I suggest we land this patch to bring meson on par with autotools, and if we decide later
> > > that autotools was wrong, we can just remove it from both places at once; ack?
> > 
> > I'd vote lets at least give Thierry till tomorrow to respond, and we can merge
> > it tomorrow around this time if he hasn't, with the remove fallback if tegra
> > shouldn't have a vdpau module? Does that sound reasonable to everyone?
> 
> Sorry, I completely missed this. Ilia is right, Tegra doesn't have any
> decoding engines in the GPU. Ilia is also correct that the engines are
> separate devices and similar to their desktop GPU counterparts. While
> it'd technically be possible to somehow enable video decoding in the
> Tegra gallium driver (I had done some prototyping on this a while ago),
> it doesn't look like the best option at this point. The problem is that
> gallium makes a bunch of assumptions that just don't apply to Tegra.
> 
> At this point, it seems more likely that video decoding will be
> implemented as V4L2 memory-to-memory drivers.
> 
> So I think we should just remove the vdpau support for Tegra from the
> autotools build. It's completely non-functional and there are no plans
> to make it work.
> 
> Thierry

Perfect, Thanks Thierry!

Dylan
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