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

[Oleksandr Andrushchenko <andr2000@gmail.com>]

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On 01/21/2017 01:01 AM, Stefano Stabellini wrote:
> On Fri, 20 Jan 2017, Oleksandr Andrushchenko wrote:
>> On 01/20/2017 07:52 PM, Stefano Stabellini wrote:
>>> On Fri, 20 Jan 2017, Oleksandr Andrushchenko wrote:
>>>> On 01/20/2017 12:22 AM, Stefano Stabellini wrote:
>>>>> On Thu, 19 Jan 2017, Oleksandr Andrushchenko wrote:
>>>>>> From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@epam.com>
>>>>>>
>>>>>> Signed-off-by: Oleksandr Andrushchenko
>>>>>> <Oleksandr_Andrushchenko@epam.com>
>>>>>> ---
>>>>>>     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:
>>>> lets break it into smaller parts
>>>>> it looks
>>>>> like multi-touch devices use the same ring and evtchn used by the
>>>>> pointer and keyboard.
>>>> *Every* multi-touch input device uses a *dedicated* event frontend/backend
>>>> *connection*
>>>> So, it is clearly stated that there is a dedicated/separate connection
>>>> (which consists of a ring and corresponding event channel: here we have
>>>> already discussed this part:
>>>> http://marc.info/?l=xen-devel&m=148412731428686):
>>>>
>>>>>>>> + * Every multi-touch input device uses a dedicated event ring and
>>>>>>>> is
>>>>>>> For clarity I would say "Every multi-touch input device uses a
>>>>>>> dedicated
>>>>>>> frontend/backend connection". That includes a ring, an event
>>>>>>> channel,
>>>>>>> and xenstore entries.
>>>>> 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.
>>>> Same as above:
>>>>
>>>> *Every* multi-touch input device uses a *dedicated* event frontend/backend
>>>> *connection*
>>>>
>>>>> If only one device is supported, do we need a XENKBD_PATH_MTOUCH folder?
>>>>>
>>>> For consistency and simplicity: at
>>>> http://marc.info/?l=xen-devel&m=148412731428686 I have an example of how
>>>> XenStore entries look like. If you define multiple mtouch devices then
>>>> you'll
>>>> iterate over folder contents, e.g.
>>>>
>>>> /local/domain/11/device/vkbd/0/mtouch/0/width = "3200"
>>>> /local/domain/11/device/vkbd/0/mtouch/1/width = "6400"
>>>>
>>>> So, you'll have something like for (i = 0; i < num_mtouch_devices; i++) {
>>>> process(i); } If you have a single mtouch device nothing changes. Thus, I
>>>> see
>>>> no reason in making any difference for single or multiple-devices.
>>> All right. I got confused because I read first the other email where you
>>> still suggested to use the other approach. Sorry. The wording is clear
>>> enough.
>> No problem, glad we are on the same page now
>>> Aside from clarity, XENKBD_PATH_MTOUCH is important to distinguish the
>>> width and height parameters of the mtouch device from the ones of the
>>> pointers device, is that right?
>> Exactly. Also for ring-ref and event-channel
> Sorry, now I am confused again :-S
In the mail-thread you mentioned above there is a picture of
the xenstore entries and conclusion:

1. No change to the existing kbd+ptr:
1.1. They still share a dedicated (single) connection
channel as they did before multi-touch: page-ref + event-channel:

/local/domain/2/device/vkbd/0/page-ref = "1248025"
/local/domain/2/device/vkbd/0/page-gref = "336"
/local/domain/2/device/vkbd/0/event-channel = "43"

1.2. No multi-touch events via that connection
1.3. Old backends/frontends will see no difference
after multi-touch

2. Each multi-touch device has its own:
2.1. Configuration (width x height, num-contacts)
2.2. Own connection channel (page-ref, event-channel)

/local/domain/2/device/vkbd/0/mtouch/0/width = "3200"
/local/domain/2/device/vkbd/0/mtouch/0/height = "3200"
/local/domain/2/device/vkbd/0/mtouch/0/num-contacts = "5"
/local/domain/2/device/vkbd/0/mtouch/0/page-ref = "1252386"
/local/domain/2/device/vkbd/0/mtouch/0/page-gref = "335"
/local/domain/2/device/vkbd/0/mtouch/0/event-channel = "44"

/local/domain/2/device/vkbd/0/mtouch/1/width = "6400"
/local/domain/2/device/vkbd/0/mtouch/1/height = "6400"
/local/domain/2/device/vkbd/0/mtouch/1/num-contacts = "10"
/local/domain/2/device/vkbd/0/mtouch/1/page-ref = "2376038"
/local/domain/2/device/vkbd/0/mtouch/1/page-gref = "337"
/local/domain/2/device/vkbd/0/mtouch/1/event-channel = "45"
So, for the example above: 1 kbd + 1 ptr + 2 mt devices
within a single driver, *3 connections*

> There are no ring-ref and event-channel under mtouch, are there?
there are ring-refs and event-channels under mtouch *per multi-touch*
device
> So, why
> would XENKBD_PATH_MTOUCH help distinguish them?
it groups multiple mtouch devices
Hope this clarifies things a bit
>>> This patch is OK as is.
>>>
>>> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
>>>
>> Thank you,
>> can I also put this "Reviewed-by" into the patch?
> Sure, unless there was a misunderstanding.
>
>
>> Anyways, I have to wait for some other comments if any
>> and publish another version of the series with
>> comments addressed ("the" in the previous patch)
>>>>>> 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?
>>>>>
>>>> Again, *Every* multi-touch input device uses a *dedicated* event
>>>> frontend/backend *connection* Thus, events are passed w/o indices via
>>>> dedicated channels
>>>>>> + * 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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