Denis 'GNUtoo' Carikli писал 04.10.2012 14:26:

On Thu, 4 Oct 2012 00:32:48 +0200 Peter Stuge peter@stuge.se wrote:

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John Case wrote:

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the real trick I am interested is isolating (or at least controlling) the interaction between the baseband processor and

the

...

application processor. Using a computer with a USB dongle gives

me

...

that control ... would I have that same level of control if we had free software running on the baseband processor, or is there still additional bleeding possible simpy by virtue of being built into the computer ?

In a smartphone it's almost not possible to distinguish the "computer" from the "GSM modem" anymore, because of how the hardware is constructed, so yes.

In some yes, in some no... it depend on how the smartphone was designed:

On one end some smartphones (openmoko GTA02,golden delicious GTA04), the baseband is isolated(tough on GTA04 it has access to a GPS with no antenna(so it can't work)) . And on the other end there are smartphones with qualcomm System on a chip...where the modem and the CPU are in a single chip: The modem part has the audio DSP connected to it, the GPS. And the baseband uses shared RAM memory and shared NAND(if I remember well)... And I'm not sure but maybe the baseband is even needed for booting the main CPU...

There are also systems in between like the galaxy S/Neuxs S that uses shared memory but do not have other problems...

In addition to the above, there are some phones where baseband is completely submissive to the AP, namely Galaxy SII. Basically it's exactly the same as the USB dongle situation, but the dongle is integrated on the phone's PCB.

Denis.