Input: xen-kbdfront - advertise either absolute or relative coordinates

A virtualized display device is usually viewed with the vncviewer
application, either by 'xm vnc domU' or with vncviewer localhost:port.
vncviewer and the RFB protocol provides absolute coordinates to the
virtual display. These coordinates are either passed through to a PV
guest or converted to relative coordinates for a HVM guest.

A PV guest receives these coordinates and passes them to the kernels
evdev driver. There it can be picked up by applications such as the
xorg-input drivers. Using absolute coordinates avoids issues such as
guest mouse pointer not tracking host mouse pointer due to wrong mouse
acceleration settings in the guests X display.

Advertise either absolute or relative coordinates to the input system
and the evdev driver, depending on what dom0 provides. The xorg-input
driver prefers relative coordinates even if a devices provides both.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 24 insertions, 20 deletions

diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
index 7f85a862ad11..53e62732ee96 100644
--- a/drivers/input/xen-kbdfront.c
+++ b/drivers/input/xen-kbdfront.c
@@ -110,7 +110,7 @@ static irqreturn_t input_handler(int rq, void *dev_id)
 static int __devinit xenkbd_probe(struct xenbus_device *dev,
                                   const struct xenbus_device_id *id)
 {
-        int ret, i;
+        int ret, i, abs;
         struct xenkbd_info *info;
         struct input_dev *kbd, *ptr;
 
@@ -128,6 +128,11 @@ static int __devinit xenkbd_probe(struct xenbus_device *dev,
         if (!info->page)
                 goto error_nomem;
 
+        if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0)
+                abs = 0;
+        if (abs)
+                xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1");
+
         /* keyboard */
         kbd = input_allocate_device();
         if (!kbd)
@@ -137,11 +142,12 @@ static int __devinit xenkbd_probe(struct xenbus_device *dev,
         kbd->id.bustype = BUS_PCI;
         kbd->id.vendor = 0x5853;
         kbd->id.product = 0xffff;
-        kbd->evbit[0] = BIT(EV_KEY);
+
+        __set_bit(EV_KEY, kbd->evbit);
         for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
-                set_bit(i, kbd->keybit);
+                __set_bit(i, kbd->keybit);
         for (i = KEY_OK; i < KEY_MAX; i++)
-                set_bit(i, kbd->keybit);
+                __set_bit(i, kbd->keybit);
 
         ret = input_register_device(kbd);
         if (ret) {
@@ -160,12 +166,20 @@ static int __devinit xenkbd_probe(struct xenbus_device *dev,
         ptr->id.bustype = BUS_PCI;
         ptr->id.vendor = 0x5853;
         ptr->id.product = 0xfffe;
-        ptr->evbit[0] = BIT(EV_KEY) | BIT(EV_REL) | BIT(EV_ABS);
+
+        if (abs) {
+                __set_bit(EV_ABS, ptr->evbit);
+                input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
+                input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
+        } else {
+                input_set_capability(ptr, EV_REL, REL_X);
+                input_set_capability(ptr, EV_REL, REL_Y);
+        }
+        input_set_capability(ptr, EV_REL, REL_WHEEL);
+
+        __set_bit(EV_KEY, ptr->evbit);
         for (i = BTN_LEFT; i <= BTN_TASK; i++)
-                set_bit(i, ptr->keybit);
-        ptr->relbit[0] = BIT(REL_X) | BIT(REL_Y) | BIT(REL_WHEEL);
-        input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
-        input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
+                __set_bit(i, ptr->keybit);
 
         ret = input_register_device(ptr);
         if (ret) {
@@ -272,7 +286,7 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
                                    enum xenbus_state backend_state)
 {
         struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
-        int ret, val;
+        int val;
 
         switch (backend_state) {
         case XenbusStateInitialising:
@@ -285,16 +299,6 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
 
         case XenbusStateInitWait:
 InitWait:
-                ret = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-                                   "feature-abs-pointer", "%d", &val);
-                if (ret < 0)
-                        val = 0;
-                if (val) {
-                        ret = xenbus_printf(XBT_NIL, info->xbdev->nodename,
-                                            "request-abs-pointer", "1");
-                        if (ret)
-                                pr_warning("can't request abs-pointer\n");
-                }
                 xenbus_switch_state(dev, XenbusStateConnected);
                 break;