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From: Andi Kleen <andi@firstfloor.org>
To: linux-kernel@vger.kernel.org, Bernhard Kaindl <bk@suse.de>,
	Andi Kleen <andi@firstfloor.org>,
	linux-usb@vger.kernel.org
Subject: Re: debugging a modern laptop ...
Date: Wed, 23 Mar 2011 05:12:56 +0100	[thread overview]
Message-ID: <20110323041256.GD21838@one.firstfloor.org> (raw)
In-Reply-To: <20110323034214.GC15541@MAIL.13thfloor.at>

> 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.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.

  reply	other threads:[~2011-03-23  4:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-23  3:42 debugging a modern laptop Herbert Poetzl
2011-03-23  4:12 ` Andi Kleen [this message]
2011-03-23 15:04 ` Alan Stern
2011-03-23 15:16   ` Mark Lord

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