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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: libps2 - better handle bad scheduler decisions
  Input: usb1400_ts - fix access to "device data" in resume function
  Input: multitouch - augment event semantics documentation
  Input: multitouch - add tracking ID to the protocol
This commit is contained in:
Linus Torvalds 2009-05-29 08:48:25 -07:00
parent 3da9e9d34e a3ce6ea46c
commit 5f789cd8ba
5 changed files with 83 additions and 26 deletions
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103
Documentation/input/multi-touch-protocol.txt
View File

@ -18,8 +18,12 @@ Usage
Anonymous finger details are sent sequentially as separate packets of ABS
events. Only the ABS_MT events are recognized as part of a finger
packet. The end of a packet is marked by calling the input_mt_sync()
function, which generates a SYN_MT_REPORT event. The end of multi-touch
transfer is marked by calling the usual input_sync() function.
function, which generates a SYN_MT_REPORT event. This instructs the
receiver to accept the data for the current finger and prepare to receive
another. The end of a multi-touch transfer is marked by calling the usual
input_sync() function. This instructs the receiver to act upon events
accumulated since last EV_SYN/SYN_REPORT and prepare to receive a new
set of events/packets.
A set of ABS_MT events with the desired properties is defined. The events
are divided into categories, to allow for partial implementation. The
@ -27,11 +31,26 @@ minimum set consists of ABS_MT_TOUCH_MAJOR, ABS_MT_POSITION_X and
ABS_MT_POSITION_Y, which allows for multiple fingers to be tracked. If the
device supports it, the ABS_MT_WIDTH_MAJOR may be used to provide the size
of the approaching finger. Anisotropy and direction may be specified with
ABS_MT_TOUCH_MINOR, ABS_MT_WIDTH_MINOR and ABS_MT_ORIENTATION. Devices with
more granular information may specify general shapes as blobs, i.e., as a
sequence of rectangular shapes grouped together by an
ABS_MT_BLOB_ID. Finally, the ABS_MT_TOOL_TYPE may be used to specify
whether the touching tool is a finger or a pen or something else.
ABS_MT_TOUCH_MINOR, ABS_MT_WIDTH_MINOR and ABS_MT_ORIENTATION. The
ABS_MT_TOOL_TYPE may be used to specify whether the touching tool is a
finger or a pen or something else. Devices with more granular information
may specify general shapes as blobs, i.e., as a sequence of rectangular
shapes grouped together by an ABS_MT_BLOB_ID. Finally, for the few devices
that currently support it, the ABS_MT_TRACKING_ID event may be used to
report finger tracking from hardware [5].
Here is what a minimal event sequence for a two-finger touch would look
like:
ABS_MT_TOUCH_MAJOR
ABS_MT_POSITION_X
ABS_MT_POSITION_Y
SYN_MT_REPORT
ABS_MT_TOUCH_MAJOR
ABS_MT_POSITION_X
ABS_MT_POSITION_Y
SYN_MT_REPORT
SYN_REPORT
Event Semantics
@ -44,24 +63,24 @@ ABS_MT_TOUCH_MAJOR
The length of the major axis of the contact. The length should be given in
surface units. If the surface has an X times Y resolution, the largest
possible value of ABS_MT_TOUCH_MAJOR is sqrt(X^2 + Y^2), the diagonal.
possible value of ABS_MT_TOUCH_MAJOR is sqrt(X^2 + Y^2), the diagonal [4].
ABS_MT_TOUCH_MINOR
The length, in surface units, of the minor axis of the contact. If the
contact is circular, this event can be omitted.
contact is circular, this event can be omitted [4].
ABS_MT_WIDTH_MAJOR
The length, in surface units, of the major axis of the approaching
tool. This should be understood as the size of the tool itself. The
orientation of the contact and the approaching tool are assumed to be the
same.
same [4].
ABS_MT_WIDTH_MINOR
The length, in surface units, of the minor axis of the approaching
tool. Omit if circular.
tool. Omit if circular [4].
The above four values can be used to derive additional information about
the contact. The ratio ABS_MT_TOUCH_MAJOR / ABS_MT_WIDTH_MAJOR approximates
@ -70,14 +89,17 @@ different characteristic widths [1].
ABS_MT_ORIENTATION
The orientation of the ellipse. The value should describe half a revolution
clockwise around the touch center. The scale of the value is arbitrary, but
zero should be returned for an ellipse aligned along the Y axis of the
surface. As an example, an index finger placed straight onto the axis could
return zero orientation, something negative when twisted to the left, and
something positive when twisted to the right. This value can be omitted if
the touching object is circular, or if the information is not available in
the kernel driver.
The orientation of the ellipse. The value should describe a signed quarter
of a revolution clockwise around the touch center. The signed value range
is arbitrary, but zero should be returned for a finger aligned along the Y
axis of the surface, a negative value when finger is turned to the left, and
a positive value when finger turned to the right. When completely aligned with
the X axis, the range max should be returned. Orientation can be omitted
if the touching object is circular, or if the information is not available
in the kernel driver. Partial orientation support is possible if the device
can distinguish between the two axis, but not (uniquely) any values in
between. In such cases, the range of ABS_MT_ORIENTATION should be [0, 1]
[4].
ABS_MT_POSITION_X
@ -98,8 +120,35 @@ ABS_MT_BLOB_ID
The BLOB_ID groups several packets together into one arbitrarily shaped
contact. This is a low-level anonymous grouping, and should not be confused
with the high-level contactID, explained below. Most kernel drivers will
not have this capability, and can safely omit the event.
with the high-level trackingID [5]. Most kernel drivers will not have blob
capability, and can safely omit the event.
ABS_MT_TRACKING_ID
The TRACKING_ID identifies an initiated contact throughout its life cycle
[5]. There are currently only a few devices that support it, so this event
should normally be omitted.
Event Computation
-----------------
The flora of different hardware unavoidably leads to some devices fitting
better to the MT protocol than others. To simplify and unify the mapping,
this section gives recipes for how to compute certain events.
For devices reporting contacts as rectangular shapes, signed orientation
cannot be obtained. Assuming X and Y are the lengths of the sides of the
touching rectangle, here is a simple formula that retains the most
information possible:
ABS_MT_TOUCH_MAJOR := max(X, Y)
ABS_MT_TOUCH_MINOR := min(X, Y)
ABS_MT_ORIENTATION := bool(X > Y)
The range of ABS_MT_ORIENTATION should be set to [0, 1], to indicate that
the device can distinguish between a finger along the Y axis (0) and a
finger along the X axis (1).
Finger Tracking
@ -109,14 +158,18 @@ The kernel driver should generate an arbitrary enumeration of the set of
anonymous contacts currently on the surface. The order in which the packets
appear in the event stream is not important.
The process of finger tracking, i.e., to assign a unique contactID to each
The process of finger tracking, i.e., to assign a unique trackingID to each
initiated contact on the surface, is left to user space; preferably the
multi-touch X driver [3]. In that driver, the contactID stays the same and
multi-touch X driver [3]. In that driver, the trackingID stays the same and
unique until the contact vanishes (when the finger leaves the surface). The
problem of assigning a set of anonymous fingers to a set of identified
fingers is a euclidian bipartite matching problem at each event update, and
relies on a sufficiently rapid update rate.
There are a few devices that support trackingID in hardware. User space can
make use of these native identifiers to reduce bandwidth and cpu usage.
Notes
-----
@ -136,5 +189,7 @@ could be used to derive tilt.
time of writing (April 2009), the MT protocol is not yet merged, and the
prototype implements finger matching, basic mouse support and two-finger
scrolling. The project aims at improving the quality of current multi-touch
functionality available in the synaptics X driver, and in addition
functionality available in the Synaptics X driver, and in addition
implement more advanced gestures.
[4] See the section on event computation.
[5] See the section on finger tracking.

1
drivers/input/input.c
View File

@ -42,6 +42,7 @@ static unsigned int input_abs_bypass_init_data[] __initdata = {
ABS_MT_POSITION_Y,
ABS_MT_TOOL_TYPE,
ABS_MT_BLOB_ID,
ABS_MT_TRACKING_ID,
0
};
static unsigned long input_abs_bypass[BITS_TO_LONGS(ABS_CNT)];

2
drivers/input/serio/libps2.c
View File

@ -210,7 +210,7 @@ int ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
timeout = wait_event_timeout(ps2dev->wait,
!(ps2dev->flags & PS2_FLAG_CMD1), timeout);
if (ps2dev->cmdcnt && timeout > 0) {
if (ps2dev->cmdcnt && !(ps2dev->flags & PS2_FLAG_CMD1)) {
timeout = ps2_adjust_timeout(ps2dev, command, timeout);
wait_event_timeout(ps2dev->wait,

2
drivers/input/touchscreen/ucb1400_ts.c
View File

@ -419,7 +419,7 @@ static int ucb1400_ts_remove(struct platform_device *dev)
#ifdef CONFIG_PM
static int ucb1400_ts_resume(struct platform_device *dev)
{
struct ucb1400_ts *ucb = platform_get_drvdata(dev);
struct ucb1400_ts *ucb = dev->dev.platform_data;
if (ucb->ts_task) {
/*

1
include/linux/input.h
View File

@ -656,6 +656,7 @@ struct input_absinfo {
#define ABS_MT_POSITION_Y 0x36 /* Center Y ellipse position */
#define ABS_MT_TOOL_TYPE 0x37 /* Type of touching device */
#define ABS_MT_BLOB_ID 0x38 /* Group a set of packets as a blob */
#define ABS_MT_TRACKING_ID 0x39 /* Unique ID of initiated contact */
#define ABS_MAX 0x3f
#define ABS_CNT (ABS_MAX+1)