<p>Fine by me. I will prepare a patch soon.</p>
<p>Thanks.</p>
<p>Julian</p>
<div class="gmail_quote">On Jan 7, 2012 9:31 PM, "Kevin O'Connor" <<a href="mailto:kevin@koconnor.net">kevin@koconnor.net</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Sat, Jan 07, 2012 at 06:27:06PM +0000, Julian Pidancet wrote:<br>
> On Thu, Jan 5, 2012 at 12:44 AM, Kevin O'Connor <<a href="mailto:kevin@koconnor.net">kevin@koconnor.net</a>> wrote:<br>
> ><br>
> > Is the issue that writes to 0x402 are causing an issue on Xen, or just<br>
> > that you don't see the debug output?<br>
> ><br>
> > What's the origin of 0xe9 - is it a "standard" for debug output? What<br>
> > does Xen do today on writes to 0xe9?<br>
> ><br>
><br>
> Xen has some sort of ring buffer similar to the linux one, that you<br>
> can access using the xl dmesg command. Every guest access to the 0xe9<br>
> port is trapped by the hypervisor which appends the characters to the<br>
> ring buffer. I doubt 0x402 does anything on Xen, aside from beeing<br>
> trapped in qemu if configured correctly, but I havn't tried.<br>
<br>
If you really want this, I'm okay with a patch that introduces<br>
CONFIG_DEBUG_PORT, and has Kconfig do all the magic of selecting the<br>
preferred debug port.<br>
<br>
That okay?<br>
<br>
-Kevin<br>
</blockquote></div>