[PATCH v2] xkb: merge lockedPtrButtons state from all attached SDs.
Peter Hutterer
peter.hutterer at who-t.net
Tue Jun 29 16:35:29 PDT 2010
Problem:
lockedPtrButtons keeps the state of the buttons locked by a PointerKeys button
press. Unconditionally clearing the bits may cause stuck buttons in this
sequence of events:
1. type Shift + NumLock to enable PointerKeys
2. type 0/Ins on keypad to emulate Button 1 press
→ button1 press event to client
3. press and release button 1 on physical mouse
→ button1 release event to client
Button 1 on the MD is now stuck and cannot be released.
Cause:
XKB PointerKeys button events are posted through the XTEST pointer device.
Once a press is generated, the XTEST device's button is down. The DIX merges
the button state of all attached SDs, hence the MD will have a button down
while the XTEST device has a button down.
PointerKey button events are only generated on the master device to avoid
duplicate events (see XkbFakeDeviceButton()). If the MD has the
lockedPtrButtons bit cleared by a release event on a physical device, no
such event is generated when a keyboard device triggers the PointerKey
ButtonRelease trigger. Since the event - if generated - is posted through
the XTEST pointer device, lack of a generated ButtonRelease event on the
XTEST pointer device means the button is never released, resulting in the
stuck button observed above.
Solution:
This patch merges the MD's lockedPtrButtons with the one of all attached
slave devices on release events. Thus, as long as one attached keyboard has
a lockedPtrButtons bit set, this bit is kept in the MD. Once a PointerKey
button is released on all keyboards, the matching release event is emulated
from the MD through the XTEST pointer device, thus also releasing the button
in the DIX.
Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
Changes to v1:
- reset lockedPtrButtons to 0 before merging
- exit early if an SD is passed to avoid state scrambling
include/xkbsrv.h | 3 +++
xkb/xkbAccessX.c | 18 +++++++++++++++++-
xkb/xkbActions.c | 8 ++++++++
xkb/xkbUtils.c | 26 ++++++++++++++++++++++++++
4 files changed, 54 insertions(+), 1 deletions(-)
diff --git a/include/xkbsrv.h b/include/xkbsrv.h
index 5847e63..956b224 100644
--- a/include/xkbsrv.h
+++ b/include/xkbsrv.h
@@ -924,6 +924,9 @@ extern int XkbGetEffectiveGroup(
XkbStatePtr /* xkbstate */,
CARD8 /* keycode */);
+extern void XkbMergeLockedPtrBtns(
+ DeviceIntPtr /* master */);
+
#include "xkbfile.h"
#include "xkbrules.h"
diff --git a/xkb/xkbAccessX.c b/xkb/xkbAccessX.c
index 6d17c75..81f9596 100644
--- a/xkb/xkbAccessX.c
+++ b/xkb/xkbAccessX.c
@@ -707,8 +707,24 @@ DeviceEvent *event = &ev->device_event;
changed |= XkbPointerButtonMask;
}
else if (event->type == ET_ButtonRelease) {
- if (xkbi)
+ if (xkbi) {
xkbi->lockedPtrButtons&= ~(1 << (event->detail.key & 0x7));
+
+ /* Merge this MD's lockedPtrButtons with the one of all
+ * attached slave devices.
+ * The DIX uses a merged button state for MDs, not
+ * releasing buttons until the last SD has released
+ * thenm. If we unconditionally clear the
+ * lockedPtrButtons bit on the MD, a PointerKeys button
+ * release on the SD keyboard won't generate the required fake button
+ * event on the XTEST pointer, thus never processing the
+ * button event in the DIX and the XTEST pointer's
+ * buttons stay down - result is a stuck button.
+ */
+ if (IsMaster(dev))
+ XkbMergeLockedPtrBtns(dev);
+ }
+
changed |= XkbPointerButtonMask;
}
diff --git a/xkb/xkbActions.c b/xkb/xkbActions.c
index d1149a1..b4b8395 100644
--- a/xkb/xkbActions.c
+++ b/xkb/xkbActions.c
@@ -634,6 +634,14 @@ _XkbFilterPointerBtn( XkbSrvInfoPtr xkbi,
}
xkbi->lockedPtrButtons&= ~(1<<button);
+ if (IsMaster(xkbi->device))
+ {
+ XkbMergeLockedPtrBtns(xkbi->device);
+ /* One SD still has lock set, don't post event */
+ if ((xkbi->lockedPtrButtons & (1 << button)) != 0)
+ break;
+ }
+
/* fallthrough */
case XkbSA_PtrBtn:
XkbFakeDeviceButton(xkbi->device, 0, button);
diff --git a/xkb/xkbUtils.c b/xkb/xkbUtils.c
index 3344e50..14dc784 100644
--- a/xkb/xkbUtils.c
+++ b/xkb/xkbUtils.c
@@ -2094,3 +2094,29 @@ XkbGetEffectiveGroup(XkbSrvInfoPtr xkbi, XkbStatePtr xkbState, CARD8 keycode)
return effectiveGroup;
}
+
+/* Merge the lockedPtrButtons from all attached SDs for the given master
+ * device into the MD's state.
+ */
+void
+XkbMergeLockedPtrBtns(DeviceIntPtr master)
+{
+ DeviceIntPtr d = inputInfo.devices;
+ XkbSrvInfoPtr xkbi = NULL;
+
+ if (!IsMaster(master))
+ return;
+
+ if (!master->key)
+ return;
+
+ xkbi = master->key->xkbInfo;
+ xkbi->lockedPtrButtons = 0;
+
+ for (; d; d = d->next) {
+ if (IsMaster(d) || GetMaster(d, MASTER_KEYBOARD) != master || !d->key)
+ continue;
+
+ xkbi->lockedPtrButtons |= d->key->xkbInfo->lockedPtrButtons;
+ }
+}
--
1.7.1
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