Re: [Xen-devel] [PATCH v1 2/2] xen/kbdif: add multi-touch support

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 19 Jan 2017, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@xxxxxxxx>
> 
> Signed-off-by: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@xxxxxxxx>
> ---
>  xen/include/public/io/kbdif.h | 216 
> ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 216 insertions(+)
> 
> diff --git a/xen/include/public/io/kbdif.h b/xen/include/public/io/kbdif.h
> index c00faa3af5d2..8d8ba9af1cb1 100644
> --- a/xen/include/public/io/kbdif.h
> +++ b/xen/include/public/io/kbdif.h
> @@ -57,6 +57,12 @@
>   *      Backends, which support reporting of absolute coordinates for pointer
>   *      device should set this to 1.
>   *
> + * feature-multi-touch
> + *      Values:         <uint>
> + *
> + *      Backends, which support reporting of multi-touch events
> + *      should set this to 1.
> + *
>   *------------------------- Pointer Device Parameters 
> ------------------------
>   *
>   * width
> @@ -87,6 +93,11 @@
>   *      Request backend to report absolute pointer coordinates
>   *      (XENKBD_TYPE_POS) instead of relative ones (XENKBD_TYPE_MOTION).
>   *
> + * request-multi-touch
> + *      Values:         <uint>
> + *
> + *      Request backend to report multi-touch events.
> + *
>   *----------------------- Request Transport Parameters 
> -----------------------
>   *
>   * event-channel
> @@ -106,6 +117,30 @@
>   *
>   *      OBSOLETE, not recommended for use.
>   *      PFN of the shared page.
> + *
> + *----------------------- Multi-touch Device Parameters 
> -----------------------
> + *
> + * Every multi-touch input device uses a dedicated event frontend/backend
> + * connection configured via XenStore properties under
> + * XENKBD_PATH_MTOUCH folder. 

This sentence doesn't seem to match the rest of the patch: it looks
like multi-touch devices use the same ring and evtchn used by the
pointer and keyboard.

Also, it is not clear whether multiple multitouch devices are supported
with a single frontend/backend connection (as you described in
http://marc.info/?l=xen-devel&m=148412731428686) or not. Please clarify.

If only one device is supported, do we need a XENKBD_PATH_MTOUCH folder?



> The values below are per emulated multi-touch
> + * input device:
> + *
> + * num-contacts
> + *      Values:         <uint>
> + *
> + *      Number of simultaneous touches reported.
> + *
> + * width
> + *      Values:         <uint>
> + *
> + *      Width of the touch area to be used by the frontend
> + *      while reporting input events, pixels, [0; UINT32_MAX].
> + *
> + * height
> + *      Values:         <uint>
> + *
> + *      Height of the touch area to be used by the frontend
> + *      while reporting input events, pixels, [0; UINT32_MAX].
>   */
>  
>  /*
> @@ -116,6 +151,16 @@
>  #define XENKBD_TYPE_RESERVED           2
>  #define XENKBD_TYPE_KEY                3
>  #define XENKBD_TYPE_POS                4
> +#define XENKBD_TYPE_MTOUCH             5
> +
> +/* Multi-touch event sub-codes */
> +
> +#define XENKBD_MT_EV_DOWN              0
> +#define XENKBD_MT_EV_UP                1
> +#define XENKBD_MT_EV_MOTION            2
> +#define XENKBD_MT_EV_SYN               3
> +#define XENKBD_MT_EV_SHAPE             4
> +#define XENKBD_MT_EV_ORIENT            5
>  
>  /*
>   * CONSTANTS, XENSTORE FIELD AND PATH NAME STRINGS, HELPERS.
> @@ -124,11 +169,17 @@
>  #define XENKBD_DRIVER_NAME             "vkbd"
>  
>  #define XENKBD_FIELD_FEAT_ABS_POINTER  "feature-abs-pointer"
> +#define XENKBD_FIELD_FEAT_MTOUCH       "feature-multi-touch"
>  #define XENKBD_FIELD_REQ_ABS_POINTER   "request-abs-pointer"
> +#define XENKBD_FIELD_REQ_MTOUCH        "request-multi-touch"
>  #define XENKBD_FIELD_RING_GREF         "page-gref"
>  #define XENKBD_FIELD_EVT_CHANNEL       "event-channel"
>  #define XENKBD_FIELD_WIDTH             "width"
>  #define XENKBD_FIELD_HEIGHT            "height"
> +#define XENKBD_FIELD_NUM_CONTACTS      "num-contacts"
> +
> +/* Path entries */
> +#define XENKBD_PATH_MTOUCH             "mtouch"
>  
>  /* OBSOLETE, not recommended for use */
>  #define XENKBD_FIELD_RING_REF          "page-ref"
> @@ -248,6 +299,170 @@ struct xenkbd_position
>      int32_t rel_z;
>  };
>  
> +/*
> + * Multi-touch event and its sub-types
> + *
> + * All multi-touch event packets have common header:
> + *
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |   event_type   |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + *
> + * event_type - unt8_t, multi-touch event sub-type, XENKBD_MT_EV_???
> + * contact_id - unt8_t, ID of the contact

If multiple devices are supported, don't we need a per multitouch device
ID to identify the source?


> + * Touch interactions can consist of one or more contacts.
> + * For each contact, a series of events is generated, starting
> + * with a down event, followed by zero or more motion events,
> + * and ending with an up event. Events relating to the same
> + * contact point can be identified by the ID of the sequence: contact ID.
> + * Contact ID may be reused after XENKBD_MT_EV_UP event and
> + * is in the [0; XENKBD_FIELD_NUM_CONTACTS - 1] range.
> + *
> + * For further information please refer to documentation on Wayland [1],
> + * Linux [2] and Windows [3] multi-touch support.
> + *
> + * [1] https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml
> + * [2] 
> https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt
> + * [3] https://msdn.microsoft.com/en-us/library/jj151564(v=vs.85).aspx
> + *
> + *
> + * Multi-touch down event - sent when a new touch is made: touch is assigned
> + * a unique contact ID, sent with this and consequent events related
> + * to this touch.
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |   _MT_EV_DOWN  |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + * |                               abs_x                               | 12
> + * +----------------+----------------+----------------+----------------+
> + * |                               abs_y                               | 16
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 20
> + * +----------------+----------------+----------------+----------------+
> + * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 40
> + * +----------------+----------------+----------------+----------------+
> + *
> + * abs_x - int32_t, absolute X position, in pixels
> + * abs_y - int32_t, absolute Y position, in pixels
> + *
> + * Multi-touch contact release event
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |  _MT_EV_UP     |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 40
> + * +----------------+----------------+----------------+----------------+
> + *
> + * Multi-touch motion event
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |  _MT_EV_MOTION |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + * |                               abs_x                               | 12
> + * +----------------+----------------+----------------+----------------+
> + * |                               abs_y                               | 16
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 20
> + * +----------------+----------------+----------------+----------------+
> + * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 40
> + * +----------------+----------------+----------------+----------------+
> + *
> + * abs_x - int32_t, absolute X position, in pixels,
> + * abs_y - int32_t, absolute Y position, in pixels,
> + *
> + * Multi-touch input synchronization event - shows end of a set of events
> + * which logically belong together.
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |  _MT_EV_SYN    |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 40
> + * +----------------+----------------+----------------+----------------+
> + *
> + * Multi-touch shape event - touch point's shape has changed its shape.
> + * Shape is approximated by an ellipse through the major and minor axis
> + * lengths: major is the longer diameter of the ellipse and minor is the
> + * shorter one. Center of the ellipse is reported via
> + * XENKBD_MT_EV_DOWN/XENKBD_MT_EV_MOTION events.
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |  _MT_EV_SHAPE  |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + * |                               major                               | 12
> + * +----------------+----------------+----------------+----------------+
> + * |                               minor                               | 16
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 20
> + * +----------------+----------------+----------------+----------------+
> + * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 40
> + * +----------------+----------------+----------------+----------------+
> + *
> + * major - unt32_t, length of the major axis, pixels
> + * minor - unt32_t, length of the minor axis, pixels
> + *
> + * Multi-touch orientation event - touch point's shape has changed
> + * its orientation: calculated as a clockwise angle between the major axis
> + * of the ellipse and positive Y axis in degrees, [-180; +180].
> + *         0                1                 2               3        octet
> + * +----------------+----------------+----------------+----------------+
> + * |  _TYPE_MTOUCH  |  _MT_EV_ORIENT |   contact_id   |    reserved    | 4
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 8
> + * +----------------+----------------+----------------+----------------+
> + * |           orientation           |            reserved             | 12
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 16
> + * +----------------+----------------+----------------+----------------+
> + * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
> + * +----------------+----------------+----------------+----------------+
> + * |                             reserved                              | 40
> + * +----------------+----------------+----------------+----------------+
> + *
> + * orientation - int16_t, clockwise angle of the major axis
> + */
> +
> +struct xenkbd_mtouch {
> +    uint8_t type;             /* XENKBD_TYPE_MTOUCH */
> +    uint8_t event_type;       /* XENKBD_MT_EV_??? */
> +    uint8_t contact_id;
> +    uint8_t reserved[5];      /* reserved for the future use */
> +    union {
> +        struct {
> +            int32_t abs_x;    /* absolute X position, pixels */
> +            int32_t abs_y;    /* absolute Y position, pixels */
> +        } pos;
> +        struct {
> +            uint32_t major;   /* length of the major axis, pixels */
> +            uint32_t minor;   /* length of the minor axis, pixels */
> +        } shape;
> +        int16_t orientation;  /* clockwise angle of the major axis */
> +    } u;
> +};
> +
>  #define XENKBD_IN_EVENT_SIZE 40
>  
>  union xenkbd_in_event
> @@ -256,6 +471,7 @@ union xenkbd_in_event
>      struct xenkbd_motion motion;
>      struct xenkbd_key key;
>      struct xenkbd_position pos;
> +    struct xenkbd_mtouch mtouch;
>      char pad[XENKBD_IN_EVENT_SIZE];
>  };
>  
> -- 
> 2.7.4
> 

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