[34-longterm 210/247] Input: xen-kbdfront - advertise either absolute or relative coordinates

Paul Gortmaker
2011-06-23T17:48:49Z

From: Olaf Hering <olaf@aepfle.de>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit 8c3c283e6bf463ab498d6e7823aff6c4762314b6 upstream.

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 <dmitry.torokhov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/input/xen-kbdfront.c | 45 ++++++++++++++++++++++-------------------
1 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
index e140816..6ad8be1 100644
--- a/drivers/input/xen-kbdfront.c
+++ b/drivers/input/xen-kbdfront.c
@@ -109,7 +109,7 @@ 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;

@@ -127,6 +127,11 @@ 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)
@@ -136,11 +141,12 @@ 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) {
@@ -159,12 +165,20 @@ 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) {
@@ -271,7 +285,7 @@ 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:
@@ -282,17 +296,6 @@ 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)
- printk(KERN_WARNING
- "xenkbd: can't request abs-pointer");
- }
xenbus_switch_state(dev, XenbusStateConnected);
break;

--
1.7.4.4