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Message-ID: <20110315050024.GB1046@core.coreip.homeip.net>
Date: Mon, 14 Mar 2011 22:00:24 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Olaf Hering <olaf@...fle.de>
Cc: Stefano Stabellini <stefano.stabellini@...citrix.com>,
linux-kernel@...r.kernel.org,
Jeremy Fitzhardinge <jeremy@...p.org>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
xen-devel@...ts.xensource.com, linux-input@...r.kernel.org
Subject: Re: [PATCH] input/xen-fbfront: advertise either absolute or relative
coordinates
On Mon, Mar 14, 2011 at 11:01:44AM +0100, Olaf Hering wrote:
> On Sat, Mar 12, Dmitry Torokhov wrote:
>
> > Hi Stefano,
> >
> > On Fri, Mar 11, 2011 at 11:30:10AM +0000, Stefano Stabellini wrote:
> > > From: Olaf Hering <olaf@...fle.de>
> > >
> > > 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.
> >
> > So if I am reading this correctly the original version handled changes
> > in backend capabilities and could switch between delivering either
> > relative or absolute coordinates. The new version selects the
> > capabilities at boot time and sticks with them. Was it really the
> > intended behavior?
>
> Yes, as mentioned in the description above, using absolute coordinates in
> the guests X11 is prefered because it avoids that the guest mouse
> pointer gets out of sync with the host/desktop mouse pointer.
> Very old Xen versions did not send absolute coordinates, but recent
> versions do.
>
OK, as long as we have understanding that there is no concern with
migrating to a version of hypervisor that does not support absolute
coordinates reporting.
BTW, I believe the code should be rearranged a bit, like in the patch
below (this way we do not set up abs params if device works in relative
mode).
Thanks.
--
Dmitry
Input: xen-kbdfront - advertise either absolute or relative coordinates
From: Olaf Hering <olaf@...fle.de>
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@...fle.de>
Signed-off-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
Signed-off-by: Dmitry Torokhov <dtor@...l.ru>
---
drivers/input/xen-kbdfront.c | 44 +++++++++++++++++++++++-------------------
1 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/drivers/input/xen-kbdfront.c b/drivers/input/xen-kbdfront.c
index 7f85a86..53e6273 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;
--
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