aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/input/input-mt.c
diff options
context:
space:
mode:
authorBenjamin Tissoires <benjamin.tissoires@redhat.com>2015-03-30 14:54:15 -0400
committerJiri Kosina <jkosina@suse.cz>2015-04-07 15:16:36 +0200
commitc627589282213bbef12a482c0b87f23526ceb3f0 (patch)
tree21f56937f6f819ce9bbc81aafdeeb2ce8a4f7938 /drivers/input/input-mt.c
parentb9e9cd32ba33d13c7ecbc15b9f4418beded403d2 (diff)
Input - mt: Fix input_mt_get_slot_by_key
The case occurred recently with a touchscreen using twice a slot during a single EV_SYN event: E: 0.288415 0000 0000 0000 # ------------ SYN_REPORT (0) ---------- E: 0.296207 0003 002f 0000 # EV_ABS / ABS_MT_SLOT 0 E: 0.296207 0003 0039 -001 # EV_ABS / ABS_MT_TRACKING_ID -1 E: 0.296207 0003 002f 0001 # EV_ABS / ABS_MT_SLOT 1 E: 0.296207 0003 0035 0908 # EV_ABS / ABS_MT_POSITION_X 908 E: 0.296207 0003 0036 1062 # EV_ABS / ABS_MT_POSITION_Y 1062 E: 0.296207 0003 002f 0000 # EV_ABS / ABS_MT_SLOT 0 E: 0.296207 0003 0039 8787 # EV_ABS / ABS_MT_TRACKING_ID 8787 E: 0.296207 0003 0035 1566 # EV_ABS / ABS_MT_POSITION_X 1566 E: 0.296207 0003 0036 0861 # EV_ABS / ABS_MT_POSITION_Y 861 E: 0.296207 0003 0000 0908 # EV_ABS / ABS_X 908 E: 0.296207 0003 0001 1062 # EV_ABS / ABS_Y 1062 E: 0.296207 0000 0000 0000 # ------------ SYN_REPORT (0) ---------- This occurred because while having already slots 0 and 1 assigned, the touchscreen sent: 0.293377 Tip Switch: 0 | Contact Id: 0 | X: 539 | Y: 1960 | Contact Count: 3 0.294783 Tip Switch: 1 | Contact Id: 1 | X: 908 | Y: 1062 | Contact Count: 0 0.296187 Tip Switch: 1 | Contact Id: 2 | X: 1566 | Y: 861 | Contact Count: 0 Slot 0 is released correclty, but when we look for Contact ID 2, the slot 0 is then picked up again because it is marked as inactive (trackingID < 0). This is wrong, and we should not reuse a slot in the same frame. The test should also check for input_mt_is_used(). In addition, we need to initialize mt->frame to an other value than 0. With mt->frame being 0, all slots are tags as currently used, and so input_mt_get_slot_by_key() would return -1 for all requests. Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=88903 Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/input/input-mt.c')
-rw-r--r--drivers/input/input-mt.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index fbe29fcb15c5..f4b58f77c524 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -88,10 +88,13 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
goto err_mem;
}
- /* Mark slots as 'unused' */
+ /* Mark slots as 'inactive' */
for (i = 0; i < num_slots; i++)
input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
+ /* Mark slots as 'unused' */
+ mt->frame = 1;
+
dev->mt = mt;
return 0;
err_mem:
@@ -430,6 +433,8 @@ EXPORT_SYMBOL(input_mt_assign_slots);
* set the key on the first unused slot and return.
*
* If no available slot can be found, -1 is returned.
+ * Note that for this function to work properly, input_mt_sync_frame() has
+ * to be called at each frame.
*/
int input_mt_get_slot_by_key(struct input_dev *dev, int key)
{
@@ -444,7 +449,7 @@ int input_mt_get_slot_by_key(struct input_dev *dev, int key)
return s - mt->slots;
for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
- if (!input_mt_is_active(s)) {
+ if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) {
s->key = key;
return s - mt->slots;
}

Privacy Policy