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

[Oleksandr Andrushchenko <andr2000@gmail.com>]

Hi, Dmitry!

It's been quite a while now, I'm just wondering if
you had a chance to look at the patch?

Thank you,
Oleksandr

On 05/12/2017 04:44 PM, Oleksandr Andrushchenko wrote:
> gentle reminder
>
>
> On 05/05/2017 07:45 AM, Oleksandr Andrushchenko wrote:
>> Hi, Dmitry!
>>
>> On 04/21/2017 09:40 AM, Oleksandr Andrushchenko wrote:
>>> Hi, Dmitry!
>>>
>>> On 04/21/2017 05:10 AM, Dmitry Torokhov wrote:
>>>> Hi Oleksandr,
>>>>
>>>> On Thu, Apr 13, 2017 at 02:38:04PM +0300, Oleksandr Andrushchenko 
>>>> wrote:
>>>>> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
>>>>>
>>>>> Extend xen_kbdfront to provide multi-touch support
>>>>> to unprivileged domains.
>>>>>
>>>>> Signed-off-by: Oleksandr Andrushchenko 
>>>>> <oleksandr_andrushchenko@epam.com>
>>>>> ---
>>>>>   drivers/input/misc/xen-kbdfront.c | 142 
>>>>> +++++++++++++++++++++++++++++++++++++-
>>>>>   1 file changed, 140 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/input/misc/xen-kbdfront.c 
>>>>> b/drivers/input/misc/xen-kbdfront.c
>>>>> index 01c27b4c3288..e5d064aaa237 100644
>>>>> --- a/drivers/input/misc/xen-kbdfront.c
>>>>> +++ b/drivers/input/misc/xen-kbdfront.c
>>>>> @@ -17,6 +17,7 @@
>>>>>   #include <linux/errno.h>
>>>>>   #include <linux/module.h>
>>>>>   #include <linux/input.h>
>>>>> +#include <linux/input/mt.h>
>>>>>   #include <linux/slab.h>
>>>>>     #include <asm/xen/hypervisor.h>
>>>>> @@ -34,11 +35,14 @@
>>>>>   struct xenkbd_info {
>>>>>       struct input_dev *kbd;
>>>>>       struct input_dev *ptr;
>>>>> +    struct input_dev *mtouch;
>>>>>       struct xenkbd_page *page;
>>>>>       int gref;
>>>>>       int irq;
>>>>>       struct xenbus_device *xbdev;
>>>>>       char phys[32];
>>>>> +    /* current MT slot/contact ID we are injecting events in */
>>>>> +    int mtouch_cur_contact_id;
>>>>>   };
>>>>>     enum { KPARAM_X, KPARAM_Y, KPARAM_CNT };
>>>>> @@ -47,6 +51,12 @@ module_param_array(ptr_size, int, NULL, 0444);
>>>>>   MODULE_PARM_DESC(ptr_size,
>>>>>       "Pointing device width, height in pixels (default 800,600)");
>>>>>   +enum { KPARAM_MT_X, KPARAM_MT_Y, KPARAM_MT_CNT };
>>>>> +static int mtouch_size[KPARAM_MT_CNT] = { XENFB_WIDTH, 
>>>>> XENFB_HEIGHT };
>>>>> +module_param_array(mtouch_size, int, NULL, 0444);
>>>>> +MODULE_PARM_DESC(ptr_size,
>>>>> +    "Multi-touch device width, height in pixels (default 800,600)");
>>>>> +
>>>> Why do you need separate module parameters for multi-touch device?
>>> please see below
>>>>
>>>>>   static int xenkbd_remove(struct xenbus_device *);
>>>>>   static int xenkbd_connect_backend(struct xenbus_device *, struct 
>>>>> xenkbd_info *);
>>>>>   static void xenkbd_disconnect_backend(struct xenkbd_info *);
>>>>> @@ -100,6 +110,60 @@ static irqreturn_t input_handler(int rq, void 
>>>>> *dev_id)
>>>>>                   input_report_rel(dev, REL_WHEEL,
>>>>>                            -event->pos.rel_z);
>>>>>               break;
>>>>> +        case XENKBD_TYPE_MTOUCH:
>>>>> +            dev = info->mtouch;
>>>>> +            if (unlikely(!dev))
>>>>> +                break;
>>>>> +            if (unlikely(event->mtouch.contact_id !=
>>>>> +                    info->mtouch_cur_contact_id)) {
>>>> Why is this unlikely? Does contact ID changes once in 1000 packets or
>>>> even less?
>>> Mu assumption was that regardless of the fact that we are multi-touch
>>> device still single touches will come in more frequently
>>> But I can remove *unlikely* if my assumption is not correct
>>>>> + info->mtouch_cur_contact_id =
>>>>> +                    event->mtouch.contact_id;
>>>>> +                input_mt_slot(dev, event->mtouch.contact_id);
>>>>> +            }
>>>>> +            switch (event->mtouch.event_type) {
>>>>> +            case XENKBD_MT_EV_DOWN:
>>>>> +                input_mt_report_slot_state(dev, MT_TOOL_FINGER,
>>>>> +                               true);
>>>>> +                input_event(dev, EV_ABS, ABS_MT_POSITION_X,
>>>>> +                        event->mtouch.u.pos.abs_x);
>>>>> +                input_event(dev, EV_ABS, ABS_MT_POSITION_Y,
>>>>> +                        event->mtouch.u.pos.abs_y);
>>>>> +                input_event(dev, EV_ABS, ABS_X,
>>>>> +                        event->mtouch.u.pos.abs_x);
>>>>> +                input_event(dev, EV_ABS, ABS_Y,
>>>>> +                        event->mtouch.u.pos.abs_y);
>>>>> +                break;
>>>>> +            case XENKBD_MT_EV_UP:
>>>>> +                input_mt_report_slot_state(dev, MT_TOOL_FINGER,
>>>>> +                               false);
>>>>> +                break;
>>>>> +            case XENKBD_MT_EV_MOTION:
>>>>> +                input_event(dev, EV_ABS, ABS_MT_POSITION_X,
>>>>> +                        event->mtouch.u.pos.abs_x);
>>>>> +                input_event(dev, EV_ABS, ABS_MT_POSITION_Y,
>>>>> +                        event->mtouch.u.pos.abs_y);
>>>>> +                input_event(dev, EV_ABS, ABS_X,
>>>>> +                        event->mtouch.u.pos.abs_x);
>>>>> +                input_event(dev, EV_ABS, ABS_Y,
>>>>> +                        event->mtouch.u.pos.abs_y);
>>>>> +                break;
>>>>> +            case XENKBD_MT_EV_SYN:
>>>>> +                input_mt_sync_frame(dev);
>>>>> +                break;
>>>>> +            case XENKBD_MT_EV_SHAPE:
>>>>> +                input_event(dev, EV_ABS, ABS_MT_TOUCH_MAJOR,
>>>>> +                        event->mtouch.u.shape.major);
>>>>> +                input_event(dev, EV_ABS, ABS_MT_TOUCH_MINOR,
>>>>> +                        event->mtouch.u.shape.minor);
>>>>> +                break;
>>>>> +            case XENKBD_MT_EV_ORIENT:
>>>>> +                input_event(dev, EV_ABS, ABS_MT_ORIENTATION,
>>>>> +                        event->mtouch.u.orientation);
>>>>> +                break;
>>>>> +            }
>>>>> +            /* only report syn when requested */
>>>>> +            if (event->mtouch.event_type != XENKBD_MT_EV_SYN)
>>>>> +                dev = NULL;
>>>>>           }
>>>>>           if (dev)
>>>>>               input_sync(dev);
>>>>> @@ -115,9 +179,9 @@ static int xenkbd_probe(struct xenbus_device 
>>>>> *dev,
>>>>>                     const struct xenbus_device_id *id)
>>>>>   {
>>>>>       int ret, i;
>>>>> -    unsigned int abs;
>>>>> +    unsigned int abs, touch;
>>>>>       struct xenkbd_info *info;
>>>>> -    struct input_dev *kbd, *ptr;
>>>>> +    struct input_dev *kbd, *ptr, *mtouch;
>>>>>         info = kzalloc(sizeof(*info), GFP_KERNEL);
>>>>>       if (!info) {
>>>>> @@ -152,6 +216,17 @@ static int xenkbd_probe(struct xenbus_device 
>>>>> *dev,
>>>>>           }
>>>>>       }
>>>>>   +    touch = xenbus_read_unsigned(dev->nodename,
>>>>> +                     XENKBD_FIELD_FEAT_MTOUCH, 0);
>>>>> +    if (touch) {
>>>>> +        ret = xenbus_write(XBT_NIL, dev->nodename,
>>>>> +                   XENKBD_FIELD_REQ_MTOUCH, "1");
>>>>> +        if (ret) {
>>>>> +            pr_warning("xenkbd: can't request multi-touch");
>>>>> +            touch = 0;
>>>>> +        }
>>>>> +    }
>>>>> +
>>>>>       /* keyboard */
>>>>>       kbd = input_allocate_device();
>>>>>       if (!kbd)
>>>>> @@ -208,6 +283,67 @@ static int xenkbd_probe(struct xenbus_device 
>>>>> *dev,
>>>>>       }
>>>>>       info->ptr = ptr;
>>>>>   +    /* multi-touch device */
>>>>> +    if (touch) {
>>>>> +        int num_cont, width, height;
>>>>> +
>>>>> +        mtouch = input_allocate_device();
>>>>> +        if (!mtouch)
>>>>> +            goto error_nomem;
>>>>> +
>>>>> +        num_cont = xenbus_read_unsigned(info->xbdev->nodename,
>>>>> +                        XENKBD_FIELD_MT_NUM_CONTACTS,
>>>>> +                        1);
>>>>> +        width = xenbus_read_unsigned(info->xbdev->nodename,
>>>>> +                         XENKBD_FIELD_MT_WIDTH,
>>>>> +                         XENFB_WIDTH);
>>>>> +        height = xenbus_read_unsigned(info->xbdev->nodename,
>>>>> +                          XENKBD_FIELD_MT_HEIGHT,
>>>>> +                          XENFB_HEIGHT);
>>>> Curious why you need separate parameters here too...
>>> This is because mt parameters are different from ptr
>>> in a way that they are configurable per front driver's
>>> instance rather than per backend, e.g. in XenStore:
>>>
>>> /local/domain/0/backend/vkbd/1/0/width = "1920"
>>> /local/domain/0/backend/vkbd/1/0/height = "1080"
>>>
>>> /local/domain/1/device/vkbd/0/multi-touch-width = "1920"
>>> /local/domain/1/device/vkbd/0/multi-touch-height = "1080"
>>> /local/domain/1/device/vkbd/0/multi-touch-num-contacts = "10"
>>>
>>> /local/domain/1/device/vkbd/1/multi-touch-width = "800"
>>> /local/domain/1/device/vkbd/1/multi-touch-height = "600"
>>> /local/domain/1/device/vkbd/1/multi-touch-num-contacts = "3"
>>>
>>> The main reason for such configuration is that you can
>>> configure multiple mt input devices even for the same guest
>>> with different resolutions which may not match those
>>> configured for ptr.
>>> (In my use-case I use new displif protocol [1] in conjunction
>>> with mt input devices and the corresponding backend is not
>>> QEMU's xenfb)
>>>
>>> As to module parameters, I added those to be consistent with
>>> ptr device. Do you think we can live without them and
>>> do you want me to remove them?
>>>>> +
>>>>> +        mtouch->name = "Xen Virtual Multi-touch";
>>>>> +        mtouch->phys = info->phys;
>>>>> +        mtouch->id.bustype = BUS_PCI;
>>>>> +        mtouch->id.vendor = 0x5853;
>>>>> +        mtouch->id.product = 0xfffd;
>>>>> +
>>>>> +        __set_bit(EV_ABS, mtouch->evbit);
>>>>> +        __set_bit(EV_KEY, mtouch->evbit);
>>>>> +        __set_bit(BTN_TOUCH, mtouch->keybit);
>>>>> +
>>>>> +        input_set_abs_params(mtouch, ABS_X,
>>>>> +                     0, width, 0, 0);
>>>>> +        input_set_abs_params(mtouch, ABS_Y,
>>>>> +                     0, height, 0, 0);
>>>>> +        input_set_abs_params(mtouch, ABS_PRESSURE,
>>>>> +                     0, 255, 0, 0);
>>>>> +
>>>>> +        input_set_abs_params(mtouch, ABS_MT_TOUCH_MAJOR,
>>>>> +                     0, 255, 0, 0);
>>>>> +        input_set_abs_params(mtouch, ABS_MT_POSITION_X,
>>>>> +                     0, width, 0, 0);
>>>>> +        input_set_abs_params(mtouch, ABS_MT_POSITION_Y,
>>>>> +                     0, height, 0, 0);
>>>>> +        input_set_abs_params(mtouch, ABS_MT_PRESSURE,
>>>>> +                     0, 255, 0, 0);
>>>>> +
>>>>> +        input_mt_init_slots(mtouch, num_cont, 0);
>>>>> +
>>>>> +        mtouch_size[KPARAM_MT_X] = width;
>>>>> +        mtouch_size[KPARAM_MT_Y] = height;
>>>>> +        info->mtouch_cur_contact_id = -1;
>>>>> +
>>>>> +        ret = input_register_device(mtouch);
>>>>> +        if (ret) {
>>>>> +            input_free_device(mtouch);
>>>>> +            xenbus_dev_fatal(info->xbdev, ret,
>>>>> +                     "input_register_device(mtouch)");
>>>>> +            goto error;
>>>>> +        }
>>>>> +        info->mtouch_cur_contact_id = -1;
>>>>> +        info->mtouch = mtouch;
>>>>> +    }
>>>>> +
>>>>>       ret = xenkbd_connect_backend(dev, info);
>>>>>       if (ret < 0)
>>>>>           goto error;
>>>>> @@ -240,6 +376,8 @@ static int xenkbd_remove(struct xenbus_device 
>>>>> *dev)
>>>>>           input_unregister_device(info->kbd);
>>>>>       if (info->ptr)
>>>>>           input_unregister_device(info->ptr);
>>>>> +    if (info->mtouch)
>>>>> +        input_unregister_device(info->mtouch);
>>>>>       free_page((unsigned long)info->page);
>>>>>       kfree(info);
>>>>>       return 0;
>>>>> -- 
>>>>> 2.7.4
>>>>>
>>>> Thanks.
>>> Thank you,
>>> Oleksandr
>>> [1] 
>>> https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git/commit/?h=for-linus-4.12&id=e27c533dc4d0338266ccb6dab428150d4d629e6a
>>>
>>
>> As all the dependencies are now merged into the kernel and *if*
>> the above sounds reasonable for you can we please proceed with this 
>> patch?
>>
>> Thank you,
>> Oleksandr
>