[Spice-devel] Note on failure w/ qemu < 1.2

[Jeremy White]

I discovered late last week that my patch
beccf8e81ea6bb4c86bcaf3cd4aac5e18f6d3f0d:
  Establish a preferred default of 1024x768 correctly.

causes a failure if running a Linux guest VM with an older host qemu
(qemu < 1.2).

This comes about because the video ram allocated
by older qemu versions (8M) is not enough to hold the
default heads (4) times the default screen size (1024x768).

It worked previously because the previous code was a bit of a mess; it
would hard code 1024x768, and it all worked out, because a resize came
through shortly to 'fix' things.

After investigating, it appeared to me that the failure was a disconnect
between our randr code and our screen setup code.  Our randr code was
acting as though all 4 heads were initially connected, resulting in a
virtual screen size of 4096x768.

I believe the patch I submitted prior to this email fixes this
correctly, by also having the randr code start with only one
connected monitor.

Cheers,

Jeremy