[Spice-commits] server/display-channel.c

[Jonathon Jongsma]

 server/display-channel.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

New commits:
commit eb3d2bfcfd6fe2495202f489f38b0d3718816dab
Author: Jonathon Jongsma <jjongsma at redhat.com>
Date:   Tue Jan 31 13:59:44 2017 -0600

    Don't close all but one display during reboot.
    
    When a guest is rebooted, the QXL driver gets unloaded at some point in
    the reboot process. When the driver is unloaded, the spice server sets a
    single flag to FALSE: RedWorker::driver_cap_monitors_config. This flag
    indicates whether the driver is capable of sending its own monitors config
    messages to the client.
    
    The only place this flag is used is when a new primary surface is created. If
    this flag is true, the server assumes that the driver will send its own
    monitors config very soon after the surface is created. If it's false, the
    server directly sends its own temporary monitors config message to the client
    based on the size of the just-created primary surface. This temporary monitors
    config message always has a maximum monitor count of 1.
    
    This flag is set to false at startup so that in early boot (e.g. vga text
    mode), the server will send out these 'temporary' monitor config messages to
    the client whenever the primary surface is destroyed and re-created. This
    causes the client to resize its window to match the size of the guest. When the
    QXL driver is loaded and starts taking over the monitors config
    responsibilities, we set this flag to true and the server stops sending
    monitors config messages out on its own.
    
    If we reboot and set this flag to false, it will result in the server sending a
    monitors config message to the client indicating that the guest now supports a
    maximum of 1 monitor. If the guest happens to have more than one display window
    open, it will destroy those extra windows because they exceed the maximum
    allowed number of monitors. This means that if you reboot a guest with 4
    monitors, after reboot it will only have 1 monitor.
    
    To avoid this, we assume that if we had the ability to support multiple
    monitors at some point, that will return at some point. So when the server
    constructs its own monitors config message to send to the client (when the
    driver_cap_monitors_config flag is false), we send the previous maximum monitor
    count instead of always sending a maximum of 1.
    
    Resolves: rhbz#1274447
    Signed-off-by: Jonathon Jongsma <jjongsma at redhat.com>
    Acked-by: Frediano Ziglio <fziglio at redhat.com>

diff --git a/server/display-channel.c b/server/display-channel.c
index bfff413b..3864419b 100644
--- a/server/display-channel.c
+++ b/server/display-channel.c
@@ -2447,15 +2447,18 @@ void display_channel_set_monitors_config_to_primary(DisplayChannel *display)
 {
     DrawContext *context = &display->priv->surfaces[0].context;
     QXLHead head = { 0, };
+    uint16_t old_max = 1;
 
     spice_return_if_fail(display->priv->surfaces[0].context.canvas);
 
-    if (display->priv->monitors_config)
+    if (display->priv->monitors_config) {
+        old_max = display->priv->monitors_config->max_allowed;
         monitors_config_unref(display->priv->monitors_config);
+    }
 
     head.width = context->width;
     head.height = context->height;
-    display->priv->monitors_config = monitors_config_new(&head, 1, 1);
+    display->priv->monitors_config = monitors_config_new(&head, 1, old_max);
 }
 
 void display_channel_reset_image_cache(DisplayChannel *self)