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kfraser@localhost.localdomain
efe6d12251
1. XendDomainInfo._createDevices() gets a list of devices to be
created from XendConfig.ordered_device_refs().
On a simple guest, this has 4 devices, vfb, vbd, vif, vkbd - in
that order.
2. It iterates over those devices, creating the appropriate
DevController subclass instance, and then calling createDevice()
on that object.
3. When createDevice() is called on the vfb device, it spawns
xen-vncfb daemon.
4. During startup xen-vncfb writes into the backend paths
/local/domain/0/backend/vfb/0
And
/local/domain/0/backend/vkbd/0
5. When createDevice() is called on the vkbd device in XenD, if the
2nd xenstore path write from step 4 has occurred, then you'll hit
the 'Device 0 (vkbd) is already connected' error. If the 2nd path
write didn't complete yet then everything is fine.
I think the reason it often works once after boot is that loading
xen-vncfb from disk the first time around is just enough of a slow
down to ensure step 5 occurs before the 2nd xenstore write in step 4
has occurred.
The key seems to be to ensure the vkbd device is initialized in
xenstore before the vfb device - this ensures all the xenstored setup
from XenD is complete before the xen-vncfb daemon starts. I'm now able
to create & destroy a domain many times over with this patch & never
hit the error message any more.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The file test.py here is from the Zope project, and is Copyright (c) 2001, 2002 Zope Corporation and Contributors. This file is released under the Zope Public License, version 2.0, a copy of which is in the file ZPL-2.0.