[Pkg-xen-devel] xen 2.6.26 on amd64 console troubles

[Ian Campbell]

On Fri, 2008-10-10 at 12:00 +0100, Ian Campbell wrote:
> On Fri, 2008-10-10 at 12:38 +0200, Bastian Blank wrote:
> > On Fri, Oct 10, 2008 at 11:20:52AM +0100, Ian Campbell wrote:
> > > You could try using xvc rather than hvc. That was the previous name of
> > > hvc in the old trees.
> > > I'm not convinced we actually want this aspect of the SuSE patch,
> > > Bastian what do you think?
> > 
> > I tried to use the hvc driver for the console and failed.
> 
> If I can get it to work would you be happy with the change?
> 
> It works for me in the non-SuSE paravirt trees so I think it's just a
> case of reverting the right bits of that patch.

It turns out that the secret is "xvc=off" on the command line, so this
configuration works:
        di64:~# cat /proc/cmdline 
        root=/dev/xvda1 ro console=hvc0 xencons=off quiet
        di64:~# ls /dev/?vc*
        /dev/hvc0  /dev/hvc2  /dev/hvc4  /dev/hvc6
        /dev/hvc1  /dev/hvc3  /dev/hvc5  /dev/hvc7
        di64:~# grep vc /etc/inittab 
        co:2345:respawn:/sbin/getty hvc0 9600 linux
        
If I don't have xvc=off then /dev contains xvc0 and not hvc* and I have
to move my getty to xvc0. I think the two can't co-exist because they
both want to access the same shared ring and event channel, even though
they have different major numbers (xvc=204 and hvc=229).

I think we should make xvc default to off and then the new hvc behaviour
would be the default and people who want to use the legacy xvc stuff can
explicitly enable it on the command line with xencons=xvc|tty|ttyS. IOW
a patch like:

--- drivers/xen/console/console.c.orig	2008-10-16 19:33:22.000000000 +0100
+++ drivers/xen/console/console.c	2008-10-16 19:33:29.000000000 +0100
@@ -73,7 +73,7 @@
  */
 static enum {
 	XC_OFF, XC_TTY, XC_SERIAL, XC_XVC
-} xc_mode = XC_XVC;
+} xc_mode = XC_OFF;
 static int xc_num = -1;
 
 /* /dev/xvc0 device number allocated by lanana.org. */



-- 
Ian Campbell

High heels are a device invented by a woman who was tired of being kissed
on the forehead.
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