[Arm-netbook] ingenic jz4760 (600mhz, MIPS, X-Burst, 720p), FSF Hardware-Endorseable

[Gordan Bobic]

 On Tue, 3 Jan 2012 13:55:04 +0000, lkcl luke <luke.leighton at gmail.com> 
 wrote:
> On Tue, Jan 3, 2012 at 1:42 PM, Gordan Bobic <gordan at bobich.net> 
> wrote:
>
>
>>  Can you elaborate how this VPU relates to the graphics subsystem on 
>> the
>>  JZ4760?
>
>  there isn't one [a graphics subsystem].  ok, there is - it has some
> 2D primitives.
>
>> What about the GPU itself? Is it little more than a dumb frame
>>  buffer and fully open?
>
>  it's fully open.  and has some basic 2D stuff.  but effectively it's
> a framebuffer.
>
>> I guess what I really want to know is whether it
>>  is possible to maintain the standard separation of functionality, 
>> e.g. a
>>  xorg driver with xv and gl acceleration? Is there such a driver 
>> already?
>
>  don't know.  probably not.  the potential of the jz4760 seems to 
> have
> completely escaped the free software community: it's not hard to see
> why - the CPU's pretty much only exclusively available in the PRC.

 OK, so we have a basic 2D frame buffer, and enough bandwidth to the 
 video RAM to do things like xv and gl acceleration in software by using 
 the VPU. Sounds to me like there is plenty of scope of writing the 
 drivers that do the job in the traditional way. The app doesn't car if 
 it's the GPU doing the number crunching or whether the driver palms it 
 off on the vector math unit. As long as the standard APIs are exposed. 
 But - do such drivers exist?

>  but, then again, the jz4740 i think it was ended up in the ben
> nanonote, so it's not all bad.

 Quick googling suggrests the Nanonote actually has a JZ4720, not 
 JZ4760.

>  the opengl library... ahh, that's a hilarious one.  the tools to do
> the X-Burst acceleration assembly-instructions are basically ... get
> this: an awk script!  so it goes hunting through c code
> (pre-processor) and substitutes hard-coded assembly instructions in
> the place of core blocks of c code!
>
>  unbelievable :)

 Umm... That is indeed quite "special".

>  so, in this way, it's using the _standard_ mesa gl source code...
> just put through a pre-processor "wringer" which gives a little bit 
> of
> extra oomph.  hilarious, but it works.


 So this awk script makes an "accelerated" driver by taking the mesa 
 source and replaces parts the software GL renderer code matching a 
 specific pattern with VPU specific assemblies?

 Wow. I wonder how many orders of magnitude more we'd get out of it with 
 a proper compiler solution...

 More to the point, I wonder how much else would benefit from this if it 
 were a proper compiler target.

>>  How does this compare to the Allwinner A10 on cost
>
>  well it has to be less.  if you look on taobao.com at qty 1 pricing
> you can find the CPU from random suppliers for 46RMB (£4.60) - but
> that's one-off quantities!
>
>  what that means is that we could actually buy all the parts 
> *without*
> having to go to Ingenic, design the board *without* having to go to
> Ingenic (because they've already released all required information).

 How does the performance compare to, say, the Marvell Armada that runs 
 at similar clock speeds?
 How much RAM can JZ4760 handle?
 What interfaces does it have? USB? SATA? PCIe?

>> and openness?
>
>  jz4760 beats the allwinner because allwinner haven't got everything
> online already available and even if they did, there's still the MALI
> 400MP to contend with.

 Which begs the question of why we aren't doing that instead...

>>  What boards/devices are available with JZ4769?
>
>  4760 not 4769.

 Sorry, fat finger error.

>  you can get MIDs on taobao.com for 300RMB (£30).

 Curious. The only thing I can find on ebay with this CPU in it is the 
 "eisse" 7in tablet with 256MB of RAM.

 With such openness, this CPU deserves to be a massive success. So why 
 are we all not voting with our feet? Why are there no products out there 
 to enable us to vote with our feet? If there is a project that has been 
 driving that point home for as long as I've been aware of it, it is this 
 one - and yet the current focus seems to be on an SoC with a closed-spec 
 GPU.

 What am I missing?

 Gordan