Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756467AbZCFPwT (ORCPT ); Fri, 6 Mar 2009 10:52:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755369AbZCFPwF (ORCPT ); Fri, 6 Mar 2009 10:52:05 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:37900 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755256AbZCFPwC (ORCPT ); Fri, 6 Mar 2009 10:52:02 -0500 Date: Fri, 6 Mar 2009 10:52:00 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Daniel Walker cc: Randy Dunlap , Yinghai Lu , , , , , , , , , , Subject: Re: [tip:x86/doc] x86/doc: mini-howto for using earlyprintk=dbgp In-Reply-To: <1236298195.5937.112.camel@desktop> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2136 Lines: 49 On Thu, 5 Mar 2009, Daniel Walker wrote: > On Thu, 2009-03-05 at 15:59 -0800, Randy Dunlap wrote: > > > > - a.) Host/target system needs to have USB debug port capability. > > > + a.) You will need two USB ports. One on the client/console system and one on > > > + the target system. > > > + > > > + b.) The client/console and target USB ports must have the debug port > > > + capability. > > > > Is that correct on the (ugh, I think that the naming/terminology is > > still mucked up, but you didn't do that) host/target system? > > > > On the client/console (which I would call the host and I would call the > > "Host/target" here just the Target system), a USB debug port is needed, > > but on the Host/target, it should just look like a USB device. > > At least that was the intent AFAIK/IIRC. No? > > > > >From the rest of document I assumed Host/target was referring to both > sides of the connection. So you would need USB on both sides for this > thing to work. I assumed Client/console was just the host. I guess that > is all kind of confusing tho .. The term "Host" is too confusing to be used here; it has too many other meanings. "Target" is good. "Client" is probably okay too, but I don't like "Console" so much because both machines will have a console. "Debugging console" is more accurate but also more cumbersome. > The document indicates you need this one capability on your USB port in > addition to the USB device (check the complete document for how to find > the capability). So both host and target need this one capability, and > then you also need the USB device for the whole thing to work. In fact the original document was rather clear about this; it says only that the target machine needs the debug capability. The client machine uses its normal USB driver and treats the debugging cable as a normal USB serial device. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/