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Date: Fri, 01 Jan 2010 19:01:51 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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Subject: Re: [Qemu-devel] [PATCH] debugcon: support for debugging consoles
	(e.g. Bochs port 0xe9)
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To: Kevin O'Connor <kevin@koconnor.net>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>, qemu-devel@nongnu.org, kraxel@redhat.com

On 12/30/2009 08:49 AM, Kevin O'Connor wrote:
> On Tue, Dec 29, 2009 at 01:51:36PM -0800, H. Peter Anvin wrote:
>> Add generic support for debugging consoles (simple I/O ports which
>> when written to cause debugging output to be written to a target.)
>> The current implementation matches Bochs' port 0xe9, allowing the same
>> debugging code to be used for both Bochs and Qemu.
>>
>> There is no vm state associated with the debugging port, simply
>> because it has none -- the entire interface is a single, stateless,
>> write-only port.
>>
>> Most of the code was cribbed from the serial port driver.
> 
> Hi,
> 
> SeaBIOS writes debugging info to port 0x0402.  Unfortunately, qemu has
> to be recompiled in order to display this info.  Will your patch
> enable one to get at the 0x0402 data without recompiling?
> 

Yes.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.