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

[Oleksandr Andrushchenko]

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@xxxxxxxx>
> > >
> > > Extend xen_kbdfront to provide multi-touch support
> > > to unprivileged domains.
> > >
> > > Signed-off-by: Oleksandr Andrushchenko 
> > > <oleksandr_andrushchenko@xxxxxxxx>
> > > ---
> > >   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