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From: Pete Zaitcev <zaitcev@redhat.com>
To: <dmitry.torokhov@gmail.com>
Cc: zaitcev@redhat.com, linux-kernel@vger.kernel.org,
	linux-input@atrey.karlin.mff.cuni.cz
Subject: Fix sudden warps in mousedev
Date: Sat, 24 Mar 2007 00:16:10 -0700	[thread overview]
Message-ID: <20070324001610.724a820a.zaitcev@redhat.com> (raw)

Here's another one of those soon-to-be-obsoleted patches to mousedev.
But if it lives just in 2.6.21, it's good, right? It's a pure bugfix.

On my laptop with Synaptics, if I lift the finger and place it elsewhere,
the pointer sometimes warps dramatically. Here's the evtest trace
which illustrates what happens:

Event: time 1174703240.830555, type 3 (Absolute), code 0 (X), value 3907
Event: time 1174703240.830557, type 3 (Absolute), code 1 (Y), value 3684
Event: time 1174703240.830561, -------------- Report Sync ------------
Event: time 1174703240.842205, type 3 (Absolute), code 0 (X), value 3909
Event: time 1174703240.842208, type 3 (Absolute), code 1 (Y), value 3687
         <---- value used by fy(2) later
Event: time 1174703240.842211, -------------- Report Sync ------------
Event: time 1174703240.854912, type 3 (Absolute), code 24 (Pressure), value 30
Event: time 1174703240.854917, -------------- Report Sync ------------
Event: time 1174703240.867130, type 1 (Key), code 330 (Touch), value 0
         <---- touch=0 now, we drop pkt_count here
Event: time 1174703240.867133, type 3 (Absolute), code 0 (X), value 3913
Event: time 1174703240.867135, type 3 (Absolute), code 1 (Y), value 3699
Event: time 1174703240.867137, type 3 (Absolute), code 24 (Pressure), value 17
Event: time 1174703240.867139, -------------- Report Sync ------------
Event: time 1174703240.877716, type 3 (Absolute), code 0 (X), value 3899
Event: time 1174703240.877718, type 3 (Absolute), code 1 (Y), value 3720
Event: time 1174703240.877721, type 3 (Absolute), code 24 (Pressure), value 8
Event: time 1174703240.877723, type 3 (Absolute), code 28 (Tool Width), value 5
Event: time 1174703240.877725, -------------- Report Sync ------------
Event: time 1174703240.891954, type 3 (Absolute), code 0 (X), value 3898
Event: time 1174703240.891957, type 3 (Absolute), code 1 (Y), value 3746
Event: time 1174703240.891959, type 3 (Absolute), code 24 (Pressure), value 5
Event: time 1174703240.891960, type 3 (Absolute), code 28 (Tool Width), value 6
Event: time 1174703240.891965, -------------- Report Sync ------------
Event: time 1174703240.918746, type 3 (Absolute), code 0 (X), value 1
Event: time 1174703240.918749, type 3 (Absolute), code 1 (Y), value 5855
Event: time 1174703240.918751, type 3 (Absolute), code 24 (Pressure), value 3
Event: time 1174703240.918753, type 3 (Absolute), code 28 (Tool Width), value 5
Event: time 1174703240.918756, type 1 (Key), code 325 (ToolFinger), value 0
Event: time 1174703240.918758, type 1 (Key), code 333 (Tool Doubletap), value 1
Event: time 1174703240.918760, -------------- Report Sync ------------
Event: time 1174703240.929545, type 3 (Absolute), code 24 (Pressure), value 2
Event: time 1174703240.929549, -------------- Report Sync ------------
Event: time 1174703241.137650, type 3 (Absolute), code 24 (Pressure), value 1
Event: time 1174703241.137655, -------------- Report Sync ------------
Event: time 1174703241.386150, type 3 (Absolute), code 24 (Pressure), value 0
Event: time 1174703241.386153, type 3 (Absolute), code 28 (Tool Width), value 0
Event: time 1174703241.386155, type 1 (Key), code 333 (Tool Doubletap), value 0
Event: time 1174703241.386158, -------------- Report Sync ------------
Event: time 1174703243.119979, type 3 (Absolute), code 0 (X), value 4763
Event: time 1174703243.119982, type 3 (Absolute), code 1 (Y), value 1964
Event: time 1174703243.119984, type 3 (Absolute), code 24 (Pressure), value 8
Event: time 1174703243.119985, type 3 (Absolute), code 28 (Tool Width), value 5
Event: time 1174703243.119987, type 1 (Key), code 325 (ToolFinger), value 1
Event: time 1174703243.119990, -------------- Report Sync ------------
Event: time 1174703243.131696, type 3 (Absolute), code 0 (X), value 4760
Event: time 1174703243.131699, type 3 (Absolute), code 1 (Y), value 1961
Event: time 1174703243.131701, type 3 (Absolute), code 24 (Pressure), value 9
Event: time 1174703243.131703, -------------- Report Sync ------------
Event: time 1174703243.143436, type 3 (Absolute), code 24 (Pressure), value 12
Event: time 1174703243.143440, type 3 (Absolute), code 28 (Tool Width), value 4
Event: time 1174703243.143442, -------------- Report Sync ------------
Event: time 1174703243.157148, type 3 (Absolute), code 24 (Pressure), value 15
Event: time 1174703243.157153, -------------- Report Sync ------------
Event: time 1174703243.169804, type 3 (Absolute), code 0 (X), value 4757
Event: time 1174703243.169806, type 3 (Absolute), code 1 (Y), value 1999
Event: time 1174703243.169808, type 3 (Absolute), code 24 (Pressure), value 18
Event: time 1174703243.169811, -------------- Report Sync ------------
Event: time 1174703243.181728, type 3 (Absolute), code 0 (X), value 4753
Event: time 1174703243.181731, type 3 (Absolute), code 24 (Pressure), value 20
Event: time 1174703243.181735, -------------- Report Sync ------------
Event: time 1174703243.193445, type 3 (Absolute), code 24 (Pressure), value 21
Event: time 1174703243.193448, -------------- Report Sync ------------
Event: time 1174703243.206640, type 3 (Absolute), code 0 (X), value 4748
Event: time 1174703243.206643, type 3 (Absolute), code 1 (Y), value 1997
Event: time 1174703243.206645, type 3 (Absolute), code 24 (Pressure), value 23
Event: time 1174703243.206647, -------------- Report Sync ------------
Event: time 1174703243.219358, type 3 (Absolute), code 24 (Pressure), value 24
Event: time 1174703243.219362, -------------- Report Sync ------------
Event: time 1174703243.231448, type 3 (Absolute), code 0 (X), value 4752
Event: time 1174703243.231450, type 3 (Absolute), code 1 (Y), value 1993
Event: time 1174703243.231452, type 3 (Absolute), code 24 (Pressure), value 25
Event: time 1174703243.231455, -------------- Report Sync ------------
Event: time 1174703243.243435, type 3 (Absolute), code 1 (Y), value 1989
Event: time 1174703243.243438, type 3 (Absolute), code 24 (Pressure), value 27
Event: time 1174703243.243440, -------------- Report Sync ------------
Event: time 1174703243.255193, type 3 (Absolute), code 0 (X), value 4748
Event: time 1174703243.255197, type 3 (Absolute), code 24 (Pressure), value 28
Event: time 1174703243.255201, -------------- Report Sync ------------
Event: time 1174703243.268904, type 3 (Absolute), code 0 (X), value 4746
Event: time 1174703243.268907, type 3 (Absolute), code 1 (Y), value 1990
Event: time 1174703243.268909, type 3 (Absolute), code 24 (Pressure), value 29
Event: time 1174703243.268911, -------------- Report Sync ------------
Event: time 1174703243.293295, type 3 (Absolute), code 1 (Y), value 1986
Event: time 1174703243.293298, type 3 (Absolute), code 24 (Pressure), value 30
Event: time 1174703243.293301, -------------- Report Sync ------------
Event: time 1174703243.305535, type 1 (Key), code 330 (Touch), value 1
          <---- touch!=0 now, we're on
Event: time 1174703243.305538, type 3 (Absolute), code 24 (Pressure), value 31
Event: time 1174703243.305541, -------------- Report Sync ------------
          <---- We increment the pkt_count, leaving value of 3687 in old_y
Event: time 1174703243.342452, type 3 (Absolute), code 0 (X), value 4747
Event: time 1174703243.342455, type 3 (Absolute), code 1 (Y), value 1988
          <----- Later to be fy(1), not used for warping purposes :-)
Event: time 1174703243.342459, -------------- Report Sync ------------
Event: time 1174703243.356225, type 3 (Absolute), code 0 (X), value 4749
Event: time 1174703243.356237, type 3 (Absolute), code 1 (Y), value 1987
          <----- warp here, by the difference of 3687 and 1987, plus
                 some small frac_dy value. Easily jumps half the screen.
Event: time 1174703243.356246, -------------- Report Sync ------------

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>

--- linux-2.6/drivers/input/mousedev.c	2007-02-11 12:38:54.000000000 -0800
+++ linux-2.6.21-input/drivers/input/mousedev.c	2007-03-23 23:47:51.000000000 -0700
@@ -274,6 +279,8 @@ static void mousedev_notify_readers(stru
 
 static void mousedev_touchpad_touch(struct mousedev *mousedev, int value)
 {
+	struct input_dev *dev;
+
 	if (!value) {
 		if (mousedev->touch &&
 		    time_before(jiffies, mousedev->touch + msecs_to_jiffies(tap_time))) {
@@ -293,8 +300,22 @@ static void mousedev_touchpad_touch(stru
 		mousedev->frac_dx = 0;
 		mousedev->frac_dy = 0;
 
-	} else if (!mousedev->touch)
+	} else if (!mousedev->touch) {
 		mousedev->touch = jiffies;
+		/*
+		 * Seed the ring with new position where finger has just landed.
+		 *
+		 * Without this, a touchpad may report an unchanged position,
+		 * then a sync. The input_event() eats the position report, but
+		 * lets the sync through. We increment pkt_count and leave 
+		 * a stale position in the ring. If a future reference to fx(2)
+		 * hits the stale position, a large dx is reported, and the
+		 * pointer warps across the screen.
+		 */
+		dev = mousedev->handle.dev;
+		fx(0) = dev->abs[ABS_X];
+		fy(0) = dev->abs[ABS_Y];
+	}
 }
 
 static void mousedev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)

             reply	other threads:[~2007-03-24  7:18 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-24  7:16 Pete Zaitcev [this message]
     [not found] ` <200703250134.03416.dtor@insightbb.com>
2007-03-25 18:19   ` Fix sudden warps in mousedev Pete Zaitcev
2007-03-26  3:19     ` Dmitry Torokhov
2007-03-26 19:17       ` Pete Zaitcev
2007-03-26 19:30         ` Dmitry Torokhov
2007-03-26 21:42           ` Pete Zaitcev
2007-03-27  1:14             ` Dmitry Torokhov
2007-03-27 15:14               ` Chuck Ebbert
2007-03-27 15:46                 ` Dmitry Torokhov
2007-03-27 16:04                   ` Chuck Ebbert
2007-03-27 16:19                     ` Dmitry Torokhov
2007-03-28 20:51                       ` Matt Keenan
2007-04-11 21:51               ` Peter Osterlund

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