Hi,
Wow, FOSDEM really was impressive this time.
There were so many people interested in the Pandora and Pyra, it's
amazing.
And even though the time for my talk was a bit too short, I think I
made myself mostly clear about what I want. Well, and if not, then you
can always ask here at the boards - and the blog entries will probably
clear up some more mysteries as well :)
Productive discussions about the OS have started on the boards as well
and I will take care about new forum sections for that tomorrow. Thanks
a lot to anyone who wants to help out here :D
One question I've seen quite a few times was "Why use the OMAP5? It has
a PowerVR chip, which doesn't have OpenSource drivers!" As mentioned,
you should take part of the Pyra development and production process -
and of course, also of the things that already happened in the past.
Especially, since that basically answers the above question as well -
so follow me on a journey...
From OMAP5 to everything else and back
Back in 2011/2012, when the OMAP5 had just been announced, we decided
to use it for the successor. It was, once again, faster than anything
else. But it seemed like TI would never even release the OMAP5...
Early 2013, TI still couldn't give any clear dates - and now Samsung,
NVidia, MediaTek, etc. were all catching up. It was clear for me that I
WILL work on a successor - and it was pretty clear that the most
complicated things to source would be the SoC and the LCD. So I started
as early as I could and contacted various other companies.
Samsung was the first company I contacted, since the German
Headquarters are in Munich, just 45 minutes away from me. The german
team did pay me a visit and they really liked the Pandora and the idea
to use a Samsung SoC for the successor. They did their best to convice
the Korean HQ, but without success. Samsung did not want to sell us
their SoC.
So I continued to search for companies.
I contacted the Freescale distriubtor, as their Cortex-A9 SoCs can be
bought without any registration and in small quantities - but
unfortunately, they decided to not produce a Cortex A15. Next stop:
MediaTek. Asian company, so probably easier to get than from the huge
global players. However, MediaTek only offer Android drivers, and they
do not plan to support Linux - well, not for our small quantities
anyways. So they decided to not sell them to us as well.
I knew from some developers that Rokchips English design manuals were
never really usable - so even if we could get the chip, we couldn't
make the hardware design without a good manual.
I tried to call nvidia a few times, but the German Headquarters never
really picked up the phone. Thanks to some contacts I had, I finally
got the right persons from nvidia worldwide headquarters on the phone -
however, only to get another "no". They explained to me that in order
to be able to use the Tegra, I need to let the hardware be designed and
produced by a contracted partner company from them. That's certainly
not what we want - and my guess is that no company would do such a
complex design as we need for such a low quantity anyways.
Things didn't look good here. There were still a few more companies who
licensed ARMs big.LITTLE architecture, so I contacted them one after
another. Most of them were in industrial / automotive business, and
they planned to have their SoC ready in 2016... a bit too late for us.
Then TIs distributor contacted us - apparently, the OMAP5 was finished
and will go into mass production in November 2013. We can still get it
if we want.
Well, we talked about the various options.
PowerVR doesn't have the sourcecode released - but then again, all
other GPU drivers in SoCs are closed source as well. I know a few will
now shout "But for MALI there's an OpenSource driver available!" -
well, yes and no. Yes, there's a driver available - but it's for the
old MALI GPU. Not a single Cortex-A15 SoC uses the old one. And it's
unknown when and whether there will be an OpenSource driver for the new
Mali as well.
TI offers Linux drivers. for their SoC and for the PowerVR.
One thing that's good about the PowerVR is that the kernel part of the
driver is not closed source - which means: While you need a binary blob
for the 3D driver, it can still be used on any compiled kernel or OS.
So when PowerVR stops development for the SGX driver, it doesn't mean
we cannot update the kernel or OS. We can. Only the 3D driver will not
be updated anymore.
While a fully OpenSource driver would be nice, there just isn't one out
there on an ARM SoC. We can't fix bugs in the 3D driver, but we won't
be stuck with an outdated kernel ever either.
You can see that on the current Pandora:
There's a small application available which lets you change the 3D
driver version on-the-fly in the running OS. Each version has different
bugs, advantages and disadvantages - but they can be run, regardless of
the kernel version.
We had a long journey, and I talked to various SoC manufacturers - and
TI turned out to be the only feasable for us. I'm pretty sure even
though it has its flaws, it will be a neat chip for our next handheld.
The horsepower I've seen so far is impressive!
Oh, and about "Why not using an Intel?"
Well... to be honest: I rather be safe and sure than risky and sorry.
When we decided what SoC to use, no one knew if the mobile market will
ever switch over to Intel. There are many Android games out there that
probably wouldn't work anymore - and we would also lose all the
optimized ARM emulators out there like PPSSPP or PCSXReARMed. Yeah, I
know, it exists for x86 as well - but it's probably not as optimized
and therefore drains more battery...
It was too risky for a small company like ourselves - so it's best to
stick to ARM right now.
Well, that's it for todays post.
I'll probably post more stuff next weekend.
If you want to join the discussion about this topic, please visit the
boards:
http://boards.openpandora.org/topic/15560-soc-back-and-forth/
-
Greetings,
Michael Mrozek aka EvilDragon
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OpenPandora GmbH
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http://www.openpandora.de/
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