[PATCH synaptic 2/2] config: don't autoprobe when device was set

[Giuseppe Bilotta]

If device was already set, we were asked to handle that specific device
and we should not go probing around. If we do, we might end up handling
a device different from what the X server thinks we are handling, with
dire consequences in case of hot plugging and unplugging.

Without this patch, a situation such as the following can happen.

A user has both a built-in laptop touchpad and a tablet such as the
Wacom Bamboo Pen & Touch, that is also exposed as a touchpad.

The tablet is plugged in before the server starts, and during setup the
server calls the synaptic driver for the /dev/input/mouseX device
corresponding to the touch device of the tablet; we end up in the
autoprobe path even though `device' was set, and the driver scans
/dev/input, where the first useful device it finds is the event device
for the built-in touchpad.

The driver starts managing the built-in touchpad, preventing future
instances from managing it too, while the server thinks the driver is
managing the tablet.

When the user disconnects the tablet, the corresponding instance of the
synpatics driver (which is actually managing the touchpad instead) is
unloaded: the built-in touchpad stops working in X.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta at gmail.com>
---
 src/synaptics.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/synaptics.c b/src/synaptics.c
index 89398f5..e0b93a0 100644
--- a/src/synaptics.c
+++ b/src/synaptics.c
@@ -275,7 +275,7 @@ SetDeviceAndProtocol(InputInfoPtr pInfo)
 	    proto = SYN_PROTO_ALPS;
 	} else { /* default to auto-dev */
 #ifdef BUILD_EVENTCOMM
-	    if (event_proto_operations.AutoDevProbe(pInfo))
+	    if (!device && event_proto_operations.AutoDevProbe(pInfo))
 		proto = SYN_PROTO_EVENT;
 #endif
 	}
-- 
1.7.3.rc1.230.gdf48043