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 <[EMAIL PROTECTED]> --- 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) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/