[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-users] Bug#708344: Serial Passthrough broken in Debian Wheezy?

On Wed, 2013-06-05 at 11:47 +0200, Jonas Meurer wrote:
> Am 2013-06-04 19:45, schrieb Ian Campbell:
> > On Tue, 2013-06-04 at 17:32 +0200, Jonas Meurer wrote:
> >> Just gave Linux 3.9-1-amd64 from Debian/sid a try. The issue is
> >> reproducible with this DomU kernel.
> > 
> > Could you post dmesg, /proc/ioports and /proc/interrupts from this
> > kernel please?
> Sure, here we go. All attached as textfiles. Additionally, I attached 
> the (adjusted) domU config.

Thanks. I'm taking this to xen-devel and moving the other two lists to
bcc. For xen-devel the background can be found at

The gist is that with:
        irq         = [ 4 ]
        ioports     = [ '3f8-3ff' ]
in the guest config the serial port used to work with Jeremy's xen.git
(used in Squeeze) but doesn't work with Wheezy (3.2 based) or a 3.9
kernel. The smstools daemon fails with:
        Cannot open serial port /dev/ttyS0, error: Function not implemented

Jonas' dmesg shows:
[    0.196892] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[    0.217565] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

and /proc/ioports shows the region but /proc/interrupts does not AFAICT.
I can't see any interrupt related errors. Jonas can you confirm that the
dmesg includes the logs resulting from an attempt to open the device?

Jonas, could you try a few more experiments, if you don't mind:

Can you use something simpler (like picocom) rather than smsdaemon and
see if that works. Assuming not could you strace it so we can see what
is actually failing. If those attempts result in anything extra in the
dmesg please can you post it.

It ought to be possible to set the port to polled mode, I think by
setting the IRQ to -1 with setserial or I think it should be possible on
the command line but I can't seem to figure out how... Anyway, if you
can get that to work it might be interesting...


Attachment: dmesg.txt
Description: Text document

Attachment: domU.cfg
Description: Text document

Attachment: proc_interrupts.txt
Description: Text document

Attachment: proc_ioports.txt
Description: Text document

Xen-users mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.