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Description of problem:

When we have to read all the pending commands from the driver's ring (red_worker.c flush_display_commands), we might need to wait for messages to be sent to the client, in case the the pipe to the client is full.
The wait timeout period was set by mistake to 150 seconds.
In case of bugs like 994175, or 977998, where the client is unresponsive, after the wait timeout expires, the server display channel disconnects from the client, and the server continues.
However, the long timeout triggers bug 994211, which can explain some of the server errors encountered in bug 964136.
Reducing the timeout to a more reasonable period (e.g. 30 seconds), will disconnect the display channel, and the server should continue normally, without
hitting bug 994211.


Steps to Reproduce:
Not 100% reproducible.
You can try disconnecting the client implicitly, by turning the client machine to sleep mode, or by disconnecting the network cable. Try to do the disconnection while there are ongoing changes made to the display.

Upstream Patch:
http://cgit.freedesktop.org/spice/spice/commit/?id=6ced0f698507de02a67cfcd25b7ab07e8c423fad

To test:
1. Connect remote-viewer to a VM.
2. Do something on the VM (e.g run a video).
3. Suspend the client (or disconnect its ethernet cable)
4. Measure the time till disconnection.
5. See if the server has errors.

(In reply to Uri Lublin from comment #2)
> To test:
> 1. Connect remote-viewer to a VM.
> 2. Do something on the VM (e.g run a video).
> 3. Suspend the client (or disconnect its ethernet cable)
> 4. Measure the time till disconnection.

Most times, only the display channel is being disconnected.
When that happens a warning is logged on the server side, such as:
 SpiceWorker-Warning **  red_worker.c:9738:flush_display_commands: update timeout

> 5. See if the server has errors.


Also, note that this is not 100% reproducible (for me it was less than 10%), and may depend on what the guest is running.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2013-1571.html