[Arm-netbook] Selecting the right Soc for out ARM Notebook project.

[Gordan Bobic]

On the subject of kernel support and GPL - if this is the key 
requirement (and let's face it, it is, without that everything else 
falls apart), then there is reasoning in using something like a Marvell 
Kirkwood + Volari combo.

Yes, the TDP would suck. SheevaPlug draws about 7W (at full load with 
gigabit ethernet working) from the plug, which is more than the AC100, 
and the AC100 figure includes the screen. The performance isn't cutting 
edge, but it is actually good enough for most things. Kirkwood is in the 
OLPC 1.75 model, IIRC (or was that the Armada?).

Anyway, you are looking at probably around 7W for the CPU+RAM, +2W for 
the Volari GPU, + 3W for the TFT panel. That's 12W. It is still very 
much in the workable passively range, and certainly less than an Atom 
laptop. Kirkwood has been fully supported in the mainline kernel for 
years, and Volari has a GPL driver, IIRC.

So for the most option _right now_, that seems like the way forward.

In the future there will be newer, better options (a year or so until 
there is a full featured production stable MALI driver, these things 
take time to stabilize), but right now, this might be a sane option.

To put some numbers on it, core-for-core and clock-for-clock, Cortex A9 
is about 2x faster than Kirkwood on compile jobs, as measured on a 
SheevaPlug (1.2GHz Kirkwood) vs. an AC100 (1.0GHz Cortex A9). But 
Kirkwood is, apparently, also available at 2GHz which might bridge the 
gap somewhat. The big problem with Kirkwood is that it is getting quite 
old and it's power management features leave much to be desired (no 
voltage/clock stepping).

Hard to match for openness and mainline kernel support, though. Shame 
that Ubuntu are dropping armv5tel support, but that only matters if you 
plan to run Ubuntu on it - and who would want to do that. ;)

Gordan