ui/vdagent: send caps on fe_open

The spice-vdagentd doesn't send capabilities again on host/client
disconnect (but when the session agent connects and sends a
GUEST_XORG_RESOLUTION message)

When the dbus client disconnects, vdagent_disconnect() is called to
reset the agent state. Capabilities must be negotiated again on
reconnection.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240717171541.201525-5-marcandre.lureau@redhat.com>

ui/vdagent.c

@@ -185,7 +185,7 @@ static void vdagent_send_msg(VDAgentChardev *vd, VDAgentMessage *msg)
     vdagent_send_buf(vd);
 }
 
-static void vdagent_send_caps(VDAgentChardev *vd)
+static void vdagent_send_caps(VDAgentChardev *vd, bool request)
 {
     g_autofree VDAgentMessage *msg = g_malloc0(sizeof(VDAgentMessage) +
                                                sizeof(VDAgentAnnounceCapabilities) +
@@ -205,6 +205,7 @@ static void vdagent_send_caps(VDAgentChardev *vd)
 #endif
     }
 
+    caps->request = request;
     vdagent_send_msg(vd, msg);
 }
 
@@ -711,7 +712,7 @@ static void vdagent_chr_recv_caps(VDAgentChardev *vd, VDAgentMessage *msg)
 
     vd->caps = caps->caps[0];
     if (caps->request) {
-        vdagent_send_caps(vd);
+        vdagent_send_caps(vd, false);
     }
     if (have_mouse(vd) && vd->mouse_hs) {
         qemu_input_handler_activate(vd->mouse_hs);
@@ -885,6 +886,7 @@ static void vdagent_chr_set_fe_open(struct Chardev *chr, int fe_open)
         return;
     }
 
+    vdagent_send_caps(vd, true);
 }
 
 static void vdagent_chr_parse(QemuOpts *opts, ChardevBackend *backend,