[Noisebridge-discuss] nVidia Tegra ARM/Geforce based Single Chip Computer

[d p chang]

"Dr. Jesus" <j at hug.gs> writes:

> On Tue, Jun 02, 2009 at 11:38:51AM -0700, d p chang wrote: 
>> > In the opensource world, who needs Intel.  I mean,
>> > seriously?http://news.prnewswire.com/ViewContent.aspx?ACC
>> 
>> anyway, i have no special knowledge of tegra, but an arm isn't doing
>> 1080p decode in software for 10hrs on battery power (at least not from
>> x264 or vc1 or one of the 'common' hd formats). if you want to do
>> something w/ your machine other than graphics you may be sol (pointer
>> chasing code isn't what gpus are good at).
>
> Which is why tegra has dedicated vector units for that stuff.  If it's
> anything like the set-top box chipsets I've worked with, the ARM
> probably just deframes the incoming stream and the decoding is done by
> special code loaded into the vector units.

there are (at least) two vector units on the tegra mumbling that google
found me. the arm11 vfp and the nvidia goo.

  http://www.nvidia.fr/object/product_tegra_600_fr.html

it looks like the 'avp' is what does the heavy lifting. the arm vfp is
nice (or nicer than their soft float), but the ones i've used wouldn't
be quite good enough (nevermind the power draw). 

> I can think of any number of chips off the top of my head which can do
> 1080p decode in less than 10 watts -- ST7109, MG3500, SH7xxx, whatever
> Toshiba shipped last year, and all those cheap MIPS SoCs coming out of
> China these days.

hmmm... i didn't think the 7109 (the only one i'm familiar w/ in your
list) did it all w/ that little power. however, i'm including the rest
of the support in my thinking of power since (i think) decode is useless
w/o a display/etc. ie, a settop box probably doesn't power the lcd/etc
off its power but would drive hdmi/component/whatever.

anyway, the point i was trying to make was that the more open arm bits
are likely going to be driving the more closed nvidia bits.

\p
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