From a718d79cc0e0c2f0aa82ba2c54383a18f15b7738 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Wed, 30 Mar 2011 22:25:34 -0700
Subject: [PATCH] Input: uinput - allow for 0/0 min/max on absolute axes.

Some devices provide absolute axes with min/max of 0/0 (e.g. wacom's
ABS_MISC axis). Current uinput restrictions do not allow duplication of
these devices and require hacks in userspace to work around this.

If the kernel accepts physical devices with a min/max of 0/0, uinput
shouldn't disallow the same range.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
 drivers/input/misc/uinput.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 364bdf43a381..736056897e50 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -302,10 +302,14 @@ static int uinput_validate_absbits(struct input_dev *dev)
 	int retval = 0;
 
 	for (cnt = 0; cnt < ABS_CNT; cnt++) {
+		int min, max;
 		if (!test_bit(cnt, dev->absbit))
 			continue;
 
-		if (input_abs_get_max(dev, cnt) <= input_abs_get_min(dev, cnt)) {
+		min = input_abs_get_min(dev, cnt);
+		max = input_abs_get_max(dev, cnt);
+
+		if ((min != 0 || max != 0) && max <= min) {
 			printk(KERN_DEBUG
 				"%s: invalid abs[%02x] min:%d max:%d\n",
 				UINPUT_NAME, cnt,
-- 
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