[PATCH/evdev] Add explicit options to ignore relative or absolute axes.

[Peter Hutterer]

The X server cannot deal with devices that have both relative and absolute
axes. Evdev tries to guess wich axes to ignore given the device type and
disables absolute axes for mice and relative axes for tablets, touchscreens
and touchpad. This guess is sometimes wrong and causes exitus felis
domesticae parvulae.

Two new configuration options are provided to explicitly allow ignoring an
axis. Mouse wheel axes are exempt and will work even if relative axes are
ignored.  No property, this configuration must be set in the configuration.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 man/evdev.man |   11 +++++++++++
 src/evdev.c   |   31 +++++++++++++++++++++++--------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/man/evdev.man b/man/evdev.man
index c3c5551..353f4f5 100644
--- a/man/evdev.man
+++ b/man/evdev.man
@@ -135,6 +135,17 @@ Default: disabled.
 .BI "Option \*qInvertY\*q \*q" Bool \*q
 Invert the given axis. Default: off. Property: "Evdev Axis Inversion".
 .TP 7
+.BI "Option \*qIgnoreRelativeAxes\*q \*q" Bool \*q
+.TP 7
+.BI "Option \*qIgnoreAbsoluteAxes\*q \*q" Bool \*q
+Ignore the specified type of axis. Default: off. The X server cannot deal
+with devices that have both relative and absolute axes. Evdev tries to guess
+wich axes to ignore given the device type and disables absolute axes for
+mice and relative axes for tablets, touchscreens and touchpad. This guess
+can be overridden with these options. Mouse wheel axes are exempt and will
+work even if relative axes are ignored. No property, this configuration must
+be set in the configuration.
+.TP 7
 .BI "Option \*qReopenAttempts\*q \*q" integer \*q
 Number of reopen attempts after a read error occurs on the device (e.g. after
 waking up from suspend). In between each attempt is a 100ms wait. Default: 10.
diff --git a/src/evdev.c b/src/evdev.c
index 2b41343..59cdd0d 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -1776,6 +1776,7 @@ EvdevProbe(InputInfoPtr pInfo)
 {
     int i, has_rel_axes, has_abs_axes, has_keys, num_buttons, has_scroll;
     int kernel24 = 0;
+    int ignore_rel, ignore_abs;
     EvdevPtr pEvdev = pInfo->private;
 
     if (pEvdev->grabDevice && ioctl(pInfo->fd, EVIOCGRAB, (void *)1)) {
@@ -1791,6 +1792,9 @@ EvdevProbe(InputInfoPtr pInfo)
         ioctl(pInfo->fd, EVIOCGRAB, (void *)0);
     }
 
+    ignore_rel = xf86SetBoolOption(pInfo->options, "IgnoreRelativeAxes", FALSE);
+    ignore_abs = xf86SetBoolOption(pInfo->options, "IgnoreAbsoluteAxes", FALSE);
+
     has_rel_axes = FALSE;
     has_abs_axes = FALSE;
     has_keys = FALSE;
@@ -1825,13 +1829,6 @@ EvdevProbe(InputInfoPtr pInfo)
     }
 
     if (has_rel_axes) {
-        xf86Msg(X_INFO, "%s: found relative axes\n", pInfo->name);
-        pEvdev->flags |= EVDEV_RELATIVE_EVENTS;
-        if (TestBit(REL_X, pEvdev->rel_bitmask) &&
-            TestBit(REL_Y, pEvdev->rel_bitmask)) {
-            xf86Msg(X_INFO, "%s: Found x and y relative axes\n", pInfo->name);
-        }
-
         if (TestBit(REL_WHEEL, pEvdev->rel_bitmask) ||
             TestBit(REL_HWHEEL, pEvdev->rel_bitmask) ||
             TestBit(REL_DIAL, pEvdev->rel_bitmask)) {
@@ -1843,6 +1840,20 @@ EvdevProbe(InputInfoPtr pInfo)
             num_buttons = (num_buttons < 3) ? 7 : num_buttons + 4;
             pEvdev->num_buttons = num_buttons;
         }
+
+        if (!ignore_rel)
+        {
+            xf86Msg(X_INFO, "%s: found relative axes\n", pInfo->name);
+            pEvdev->flags |= EVDEV_RELATIVE_EVENTS;
+
+            if (TestBit(REL_X, pEvdev->rel_bitmask) &&
+                TestBit(REL_Y, pEvdev->rel_bitmask)) {
+                xf86Msg(X_INFO, "%s: Found x and y relative axes\n", pInfo->name);
+            }
+        } else {
+            xf86Msg(X_INFO, "%s: relative axes present but ignored.\n", pInfo->name);
+            has_rel_axes = FALSE;
+        }
     }
 
     for (i = 0; i < ABS_MAX; i++) {
@@ -1852,7 +1863,11 @@ EvdevProbe(InputInfoPtr pInfo)
         }
     }
 
-    if (has_abs_axes) {
+    if (ignore_abs && has_abs_axes)
+    {
+        xf86Msg(X_INFO, "%s: absolute axes present but ignored.\n", pInfo->name);
+        has_abs_axes = FALSE;
+    } else if (has_abs_axes) {
         xf86Msg(X_INFO, "%s: found absolute axes\n", pInfo->name);
         pEvdev->flags |= EVDEV_ABSOLUTE_EVENTS;
 
-- 
1.6.3.rc1.2.g0164.dirty