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

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Oleksandr Andrushchenko <andr2000@gmail.com>
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
	linux-input@vger.kernel.org, joculator@gmail.com,
	al1img@gmail.com, vlad.babchuk@gmail.com,
	andrii.anisov@gmail.com, olekstysh@gmail.com,
	boris.ostrovsky@oracle.com, jgross@suse.com,
	Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Subject: Re: [PATCH 2/2] xen/input: add multi-touch support
Date: Thu, 20 Apr 2017 19:10:18 -0700	[thread overview]
Message-ID: <20170421021018.GB23279@dtor-ws> (raw)
In-Reply-To: <1492083484-31786-3-git-send-email-andr2000@gmail.com>

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?

>  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?

> +				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...

> +
> +		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.

-- 
Dmitry