Don't grab devices unless specified through the config options.

Grabbing event devices stops in-kernel event forwarding, most notably rfkill
and the "Macintosh mouse button emulation" device. Let's not do that.

Option "GrabDevice" forces grabbing the device.

man/evdev.man

@@ -12,6 +12,7 @@ evdev \- Generic Linux input driver
 .BI "  Option \*qPath\*q     \*q" path \*q
 .BI "  Option \*qEmulate3Buttons\*q     \*q" True \*q
 .BI "  Option \*qEmulate3Timeout\*q     \*q" 50 \*q
+.BI "  Option \*qGrabDevice\*q     \*q" False \*q
 \ \ ...
 .B EndSection
 .fi
@@ -120,6 +121,13 @@ emulation mode.  Button number
 is mapped to the negative Y axis motion and button number
 .I N2
 is mapped to the positive Y axis motion.  Default: "4 5"
+.TP 7
+.BI "Option \*qGrabDevice\*q \*q" boolean \*q
+Force a grab on the event device. Doing so will ensure that no other driver
+can initialise the same device and it will also stop the device from sending
+events to /dev/kbd or /dev/input/mice. Events from this device will not be
+sent to virtual devices (e.g. rfkill or the Macintosh mouse button emulation).
+Default disabled.
 .SH AUTHORS
 Kristian Høgsberg.
 .SH "SEE ALSO"

src/evdev.c

@@ -942,23 +942,24 @@ EvdevProc(DeviceIntPtr device, int what)
 	return EvdevInit(device);
 
     case DEVICE_ON:
-        if (!pEvdev->kernel24 && ioctl(pInfo->fd, EVIOCGRAB, (void *)1))
+        if (pEvdev->grabDevice && ioctl(pInfo->fd, EVIOCGRAB, (void *)1))
+        {
             xf86Msg(X_WARNING, "%s: Grab failed (%s)\n", pInfo->name,
                     strerror(errno));
-        if (errno != ENODEV)
+            if (errno == ENODEV)
+                return !Success;
+        }
+        xf86AddEnabledDevice(pInfo);
+        if (pEvdev->flags & EVDEV_BUTTON_EVENTS)
         {
-            xf86AddEnabledDevice(pInfo);
-            if (pEvdev->flags & EVDEV_BUTTON_EVENTS)
-            {
-                EvdevMBEmuPreInit(pInfo);
-                EvdevWheelEmuPreInit(pInfo);
-            }
-            device->public.on = TRUE;
+            EvdevMBEmuPreInit(pInfo);
+            EvdevWheelEmuPreInit(pInfo);
         }
+        device->public.on = TRUE;
 	break;
 
     case DEVICE_OFF:
-        if (!pEvdev->kernel24 && ioctl(pInfo->fd, EVIOCGRAB, (void *)0))
+        if (pEvdev->grabDevice && ioctl(pInfo->fd, EVIOCGRAB, (void *)0))
             xf86Msg(X_WARNING, "%s: Release failed (%s)\n", pInfo->name,
                     strerror(errno));
         xf86RemoveEnabledDevice(pInfo);
@@ -982,17 +983,19 @@ EvdevProbe(InputInfoPtr pInfo)
     long rel_bitmask[NBITS(REL_MAX)];
     long abs_bitmask[NBITS(ABS_MAX)];
     int i, has_axes, has_keys, num_buttons;
+    int kernel24 = 0;
     EvdevPtr pEvdev = pInfo->private;
 
-    if (ioctl(pInfo->fd, EVIOCGRAB, (void *)1)) {
+    if (pEvdev->grabDevice && ioctl(pInfo->fd, EVIOCGRAB, (void *)1)) {
         if (errno == EINVAL) {
             /* keyboards are unsafe in 2.4 */
-            pEvdev->kernel24 = 1;
+            kernel24 = 1;
+            pEvdev->grabDevice = 0;
         } else {
             xf86Msg(X_ERROR, "Grab failed. Device already configured?\n");
             return 1;
         }
-    } else {
+    } else if (pEvdev->grabDevice) {
         ioctl(pInfo->fd, EVIOCGRAB, (void *)0);
     }
 
@@ -1068,7 +1071,7 @@ EvdevProbe(InputInfoPtr pInfo)
     }
 
     if (has_keys) {
-        if (pEvdev->kernel24) {
+        if (kernel24) {
             xf86Msg(X_INFO, "%s: Kernel < 2.6 is too old, ignoring keyboard\n",
                     pInfo->name);
         } else {
@@ -1152,6 +1155,10 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
         return NULL;
     }
 
+    /* Grabbing the event device stops in-kernel event forwarding. In other
+       words, it disables rfkill and the "Macintosh mouse button emulation".  */
+    pEvdev->grabDevice = xf86CheckBoolOption(dev->commonOptions, "GrabDevice", 0);
+
     EvdevInitButtonMapping(pInfo);
 
     pEvdev->noXkb = noXkbExtension;

src/evdev.h

@@ -50,7 +50,7 @@ typedef struct {
 } WheelAxis, *WheelAxisPtr;
 
 typedef struct {
-    int kernel24;
+    int grabDevice;         /* grab the event device? */
     int screen;
     int min_x, min_y, max_x, max_y;
     int abs_x, abs_y, old_x, old_y;