By: Maynard Handley (name99.delete@this.name99.org), October 25, 2016 5:28 pm
Room: Moderated Discussions
dmcq (dmcq.delete@this.fano.co.uk) on October 25, 2016 11:07 am wrote:
> Doug S (foo.delete@this.bar.bar) on October 25, 2016 8:59 am wrote:
> > Great article, David! I had been wondering why Apple had been hiring GPU engineers for
> > years but weren't doing a custom GPU. Turned out they were, we just didn't know it.
> >
> > Interesting that they seem to be taking a slower approach towards a full custom GPU than the
> > 'big bang' they did with the A6 on the CPU side. Do you think this might have something to do
> > with patents? i.e., so long as they are co-designing with Imagination, they can effectively
> > lean on Imagination's patent agreements, whereas if they cut them out and went full custom they'd
> > need a large GPU patent warchest to obtain the necessary cross licensing agreements.
>
> I'm pretty certain it just depends on where the user interface is. For Graphics it
> is a higher level interface than it is for the CPU, they don't need compatibility of
> the graphics hardware between different versions of the iPhone whereas it was a big
> thing for the CPU - though nowhere near as bad as it would be for the Apple Macs.
An interesting place to look for changes might be investigating the Watch Series 2 GPU...
Given that this has an easier job than a full iOS GPU (officially, at least, the APIs available are SceneKit and SpriteKit, but not anything lower level like Metal or OpenGL, and no shaders), if you were wanting to implement an entire GPU from scratch including, eg, the fixed function stuff that David lists as likely being unchanged relative to Imagination, this seems like it would be the place to do it.
(MINIMAL shaders are available --- http://allanlavell.com/how-to-run-shaders-apple-watch/ )
https://developer.apple.com/library/content/releasenotes/General/WhatsNewInwatchOS/Articles/watchOS3.html
It's also a less problematic development target in that if the watch had had to be delayed a few months, no-one would have been shocked --- there was an expectation, but not a certainty, that we'd see a new model in September.
> Doug S (foo.delete@this.bar.bar) on October 25, 2016 8:59 am wrote:
> > Great article, David! I had been wondering why Apple had been hiring GPU engineers for
> > years but weren't doing a custom GPU. Turned out they were, we just didn't know it.
> >
> > Interesting that they seem to be taking a slower approach towards a full custom GPU than the
> > 'big bang' they did with the A6 on the CPU side. Do you think this might have something to do
> > with patents? i.e., so long as they are co-designing with Imagination, they can effectively
> > lean on Imagination's patent agreements, whereas if they cut them out and went full custom they'd
> > need a large GPU patent warchest to obtain the necessary cross licensing agreements.
>
> I'm pretty certain it just depends on where the user interface is. For Graphics it
> is a higher level interface than it is for the CPU, they don't need compatibility of
> the graphics hardware between different versions of the iPhone whereas it was a big
> thing for the CPU - though nowhere near as bad as it would be for the Apple Macs.
An interesting place to look for changes might be investigating the Watch Series 2 GPU...
Given that this has an easier job than a full iOS GPU (officially, at least, the APIs available are SceneKit and SpriteKit, but not anything lower level like Metal or OpenGL, and no shaders), if you were wanting to implement an entire GPU from scratch including, eg, the fixed function stuff that David lists as likely being unchanged relative to Imagination, this seems like it would be the place to do it.
(MINIMAL shaders are available --- http://allanlavell.com/how-to-run-shaders-apple-watch/ )
https://developer.apple.com/library/content/releasenotes/General/WhatsNewInwatchOS/Articles/watchOS3.html
It's also a less problematic development target in that if the watch had had to be delayed a few months, no-one would have been shocked --- there was an expectation, but not a certainty, that we'd see a new model in September.
