[Qemu-devel] [PATCH] restore mouse handler after removing usb mice

[Lonnie Mendez <lmendez19@austin.rr.com>]

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    lo list.  The attached patch allows qemu to have several mouse
handlers.  The reason for this is that adding a usb mouse/tablet will
override the primary mouse event handler so there needs to be a way of
restoring a previous mouse input handler such as the ps/2 device on the
PC system target (and/or perhaps selecting amongst the available
inputs).

    What this doesn't do is multiplex mouse inputs from all devices - as
before only one device is actively giving input.

Test case with windows xp guest.

qemu -hda winxp.qcow2 -localtime -usbdevice tablet -no-acpi
-kernel-kqemu

(qemu) usb_del 0.1  <address of usb tablet in guest>

Once the usb tablet device is removed the ps/2 input was functional
again.

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--- qemu/vl.c	2006-10-31 19:44:16.000000000 -0600
+++ qemu/vl.c	2006-11-24 23:07:26.000000000 -0600
@@ -451,9 +451,11 @@
 
 static QEMUPutKBDEvent *qemu_put_kbd_event;
 static void *qemu_put_kbd_event_opaque;
-static QEMUPutMouseEvent *qemu_put_mouse_event;
-static void *qemu_put_mouse_event_opaque;
-static int qemu_put_mouse_event_absolute;
+#define QEMU_MAX_MICE_EVENTS 3
+static int qemu_mouse_current = -1;
+static QEMUPutMouseEvent *qemu_put_mouse_event[QEMU_MAX_MICE_EVENTS];
+static void *qemu_put_mouse_event_opaque[QEMU_MAX_MICE_EVENTS];
+static int qemu_put_mouse_event_absolute[QEMU_MAX_MICE_EVENTS];
 
 void qemu_add_kbd_event_handler(QEMUPutKBDEvent *func, void *opaque)
 {
@@ -461,11 +463,26 @@
     qemu_put_kbd_event = func;
 }
 
-void qemu_add_mouse_event_handler(QEMUPutMouseEvent *func, void *opaque, int absolute)
+void qemu_add_mouse_event_handler(QEMUPutMouseEvent *func, void *opaque,
+                                  int absolute)
 {
-    qemu_put_mouse_event_opaque = opaque;
-    qemu_put_mouse_event = func;
-    qemu_put_mouse_event_absolute = absolute;
+    /* revert to previous event handler */
+    if (func == NULL &&
+        opaque == NULL) {
+        if (qemu_mouse_current >= 0) {
+            qemu_put_mouse_event[qemu_mouse_current] = NULL;
+            qemu_put_mouse_event_opaque[qemu_mouse_current] = NULL;
+            --qemu_mouse_current;
+        }
+        return;
+    }
+    
+    ++qemu_mouse_current;
+    if (qemu_mouse_current == QEMU_MAX_MICE_EVENTS)
+        qemu_mouse_current = QEMU_MAX_MICE_EVENTS - 1;
+    qemu_put_mouse_event_opaque[qemu_mouse_current] = opaque;
+    qemu_put_mouse_event[qemu_mouse_current] = func;
+    qemu_put_mouse_event_absolute[qemu_mouse_current] = absolute;
 }
 
 void kbd_put_keycode(int keycode)
@@ -477,15 +494,25 @@
 
 void kbd_mouse_event(int dx, int dy, int dz, int buttons_state)
 {
-    if (qemu_put_mouse_event) {
-        qemu_put_mouse_event(qemu_put_mouse_event_opaque, 
-                             dx, dy, dz, buttons_state);
+    QEMUPutMouseEvent *mouse_event_func;
+    
+    if (qemu_mouse_current < 0)
+        return;
+    
+    mouse_event_func = qemu_put_mouse_event[qemu_mouse_current];
+    
+    if (mouse_event_func) {
+        mouse_event_func(qemu_put_mouse_event_opaque[qemu_mouse_current], 
+                         dx, dy, dz, buttons_state);
     }
 }
 
 int kbd_mouse_is_absolute(void)
 {
-    return qemu_put_mouse_event_absolute;
+    if (qemu_mouse_current < 0)
+        return 0;
+    
+    return qemu_put_mouse_event_absolute[qemu_mouse_current];
 }
 
 /* compute with 96 bit intermediate result: (a*b)/c */
--- qemu/sdl.c	2006-08-19 09:27:30.000000000 -0500
+++ qemu/sdl.c	2006-11-24 23:14:55.000000000 -0600
@@ -319,6 +319,7 @@
 {
     if (!kbd_mouse_is_absolute()) {
         SDL_ShowCursor(1);
+        SDL_SetCursor(sdl_cursor_normal);
     }
 }
 
@@ -364,6 +365,9 @@
 	SDL_GetMouseState(&dx, &dy);
 	dx = dx * 0x7FFF / width;
 	dy = dy * 0x7FFF / height;
+    } else if (absolute_enabled) {
+	sdl_show_cursor();
+	absolute_enabled = 0;
     }
 
     kbd_mouse_event(dx, dy, dz, buttons);
@@ -499,7 +503,8 @@
             qemu_system_shutdown_request();
             break;
         case SDL_MOUSEMOTION:
-            if (gui_grab || kbd_mouse_is_absolute()) {
+            if (gui_grab || kbd_mouse_is_absolute() ||
+                absolute_enabled) {
                 sdl_send_mouse_event(0);
             }
             break;