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

From: Oleksandr Andrushchenko <andr2000@gmail.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: jgross@suse.com, vlad.babchuk@gmail.com,
	linux-kernel@vger.kernel.org, andrii.anisov@gmail.com,
	olekstysh@gmail.com, al1img@gmail.com,
	linux-input@vger.kernel.org, xen-devel@lists.xenproject.org,
	boris.ostrovsky@oracle.com, joculator@gmail.com
Subject: Re: [PATCH 2/2] xen/input: add multi-touch support
Date: Fri, 12 May 2017 16:44:06 +0300	[thread overview]
Message-ID: <8d522e12-8a1b-1eb4-981c-9bb1042e9703__30078.1642007225$1494596711$gmane$org@gmail.com> (raw)
In-Reply-To: <8a43bbdf-f843-2c4d-e7b7-0cddb2e7fd7e@gmail.com>

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


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel