Intel's UXA Will Not Be Merged Back Into EXA

[phoronix]

Phoronix: Intel's UXA Will Not Be Merged Back Into EXA

Back in August we talked about the UXA acceleration architecture, which was developed by Intel and based upon EXA but pixmaps were dealt with as GEM objects. A month later at the X Developers' Summit, Keith Packard had clarified his UXA work. At that time he said the information learned from UXA would work its way back into EXA by separating the pixmap management and acceleration components of EXA...

http://www.phoronix.com/vr.php?view=NzA0NQ

[bugmenot]

I don't think this is soo bad. It's a bit like the thing with radeon/radeonhd: The advantage of radeonhd is that it supports less hardware and so it is smaller, smarter and more compact. And if it's a new accel technology, why not. Even if it's in fact only an extended EXA. And even (or just because) if it's only useful for IGPs.

[Craig73]

I'd be curious as to the architectural reasons why, but I suppose we have to wait for the videos/minutes.

[drag]

I'd be curious as to the architectural reasons why, but I suppose we have to wait for the videos/minutes.

Probably because there isn't any point in merging it back into the EXA drivers.

Just like it was pointless to try to take the existing legacy EXA DDX stuff and extend it to create a functional equivalent to UXA, it's pointless to try to backport UXA into EXA legacy DDX.

If UXA works, then why should you give a darn about sucking it into EXA? Just use UXA. Done. Get rid of EXA completely, throw it down the bit-bin of history... The EXA API was sort of designed, on purpose, to be driven by 3D graphics hardware and have a relatively short life as a 2D driven API. I think most X.org people understood that 2D hardware in Video cards is a dying thing... even modern cards with 2D hardware the 2D cores are essentially unchanged from when they were originally designed back in the Gefore 256 days (circa 1999).

As far as programs go it shouldn't matter. Both implement the EXA API, so programs and end users shouldn't give a darn one way or the other. The only way it would matter to end users is if they experience a difference in performance and/or reliability.

[stan]

They never intended to help out other drivers by improving EXA incrementally. I could have told you this the moment Intel started putting

#if I830_USE_UXA

into their driver. This showed they considered EXA and UXA distinct frameworks.

[Craig73]

...If UXA works, then why should you give a darn about sucking it into EXA? Just use UXA. Done...

In it of itself, I don't. I don't advocate endless support of hardware (especially since the power/performance/energy cost ratios might suggest some is cheaper to replace), but there is plenty of capable hardware out there for general applications, and as I see plenty of these interesting new features being implemented I wonder how that older hardware could benefit. IE - would improved 2D performance on an older system mean my computer is relevant just a little longer, or that CPU performance can be put to more useful purpose. So when new APIs are implemented it tends to leave older drivers behind...

I don't want to hinder progress, new features, and all of Intel's great work. I'm not even pretending to have a full understanding of the implications. I just was posing the question because I was curious, and trying to see the bigger picture.

[bridgman]

If UXA works, then why should you give a darn about sucking it into EXA? Just use UXA. Done. Get rid of EXA completely, throw it down the bit-bin of history...

I think the point is that UXA only works for integrated graphics processors where video memory = system memory. You would still need EXA for GPUs with dedicated video memory.

[MrCooper]

Even if it's in fact only an extended EXA.

Actually, it's a stripped down EXA. The sad thing is that the main benefit of UXA (storing pixmaps in buffer objects) could already be done with EXA before UXA existed, and the parts they stripped from EXA would be inactive anyway in that case. There are academic problems with the EXA driver interfaces for this, but I think it would have been better to fix those than to create yet another acceleration architecture. Why they chose differently is anyone's guess.

[RealNC]

So that Intel has a lead since their drivers now use UXA.

[TechMage89]

As far as I understand, the only advantage of UXA is that IGPs don't have to make an extra copy. For discrete cards, it offers no real advantages that can't be done with EXA.

Also, saying that 2d acceleration is on the way out is kind of silly. It may be true in the future that 2d will be treated simply as a subset of 3d, but that doesn't mean it will go away. There are still servers and other applications that don't need 3d, but do need fast 2d (for UI.)