+++ Steve Wiseman [2011-05-24 08:04 +0100]:
>
> On Tue 24/05/11 07:16 , "P.J.G. Long" <pjgl2@cam.ac.uk> wrote:
>
> > The low end console/display market seems to be moving HDMI, they are
> > becoming more common on netbooks. I can see for a number of low end
> > users using it as the cheap route to a display. See the Raspberry! Looking
> > at the feedback I think there may be a market for the Balloon as the up
> > market interfacable unit
>
> This still isn't a use case.
> Is it simply that, without a monitor connection of some sort, it's not a 'proper computer?
To some degree, yes. It's certainly not a convenient computer, although ssh and
remote X goes a long way to solving this in a different way.
> During development, there will always be a desktop / laptop machine
> being used for compilation, and it'll have a decent display, on which
> X works well, also serial terminals, xterms, ssh, whatever. Who really
> wants yet another monitor on their precious desk space, running scaled
> HDMI? That implies another keyboard, too.
Not if you do native development, which is what Debian and Ubuntu push
you towards and it's more and more practical as the arm hardware gets
better. Balloon4 will be at least as fast as a PC from a few years
back (pentium III?) and native dev there was no problem.
> In short: If you want to drive an HDMI TV, a PC is probably cheaper.
> You've obviously got mains available, so you don't care about power.
Wrong. I always care about power. And so should everyone.
> You've obviously got space available, so stick a Revo on the back of
> your TV if you want to pretend to be 'integrated'.
> If I exposed the DSS as 28 precious GPIOs on a connector, (or 24
> GPIOs and SPI3), and let people add an HDMI chip & connector, would we
> sell any of those, ever?
> Would we sell any IO boards that sat there instead and protected
> those (1.8V) GPIO pins, and exposed them at student-friendly levels &
> connectors?
This is the real question. Is it worth the pins? I don't have an
answer to that. So long as we are happy with the answer 'go buy a
beagle if you wanted to plug it into a TV' then we don't need it.
Ethernet and DVI/VGA/HDMI are incredibly convenient for development.
If we only provide those on a dev-board then that's OK, but lets try
not to have a 3-yr gap between board and dev-board this time in that
case. Ethernet is more important than video.
> If DVI/HDMI over USB works as well as it seems, then why would we
> want to sit there squandering precious memory bandwidth spewing pixels
> down a wire? Plug in a display when you want to do a demo on a
> projector or something, but the other 99% of the time, run headless.
> (The memory bandwidth issue isn't specious. 720p60 is 240MBytes a
> second, of unstoppable high priority data. Not sure if it pollutes the
> cache or not.)
If it does indeed work over USB then that's OK, (do we have 240MB/s
over USB?) And do we have enough USB sockets for ethernet, video,
serial, keyboard, <something else>? The need for a hub to do almost
anything on B3 was tiresome in practice.
> (I'm trying to think of a time when you'd want both Balloon's FPGA
> resource, and a genuine framebuffered, pixel-painting display on a TV,
> and I can't. Something that needed the 3D graphics engine of the OMAP,
> on a projector, maybe?)
I amdit I don;t understand the difference between LCD and
DVI/VGA/HDMI. Don't they all amount to "a genuine framebuffered,
pixel-painting display"?
Any display will do, widely available ones with standard connections
are just easy to dev with.
Wookey
--
Principal hats: Linaro, Emdebian, Wookware, Balloonboard, ARM
http://wookware.org/
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