Re: debugging a modern laptop ...

From: Andi Kleen
Date: Wed Mar 23 2011 - 00:13:05 EST

> most modern devices have at least one usb port, but as far
> as I could figure out via google, there is no support for
> console or similar over usb (serial or not) atm
> (please feel free to correct me here :)

There is also USB debugport, but you need a quite expensive cable
(~$100) for it. Usually it only works on one of the USB ports.

> after some research, I also found a quite antique project
> exploiting the ieee1394 DMA feature, called firescope and
> after some issues finding the latest version of the tool and
> of course getting a firewire cable, there seems to be some
> kind of interaction between the monitoring system and the
> device in question, but it seems that a few problems exist
> and I didn't manage to get any relevant information that
> way yet (please let me know if that is still maintained)

It works, but you need to enable it of course. The printk
buffer hasn't changed for a long time.

The only problem often is that it doesn't support memory >4GB,
however it turns out that some LSI chips support >4GB DMA
and with those it works too.

ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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