[v5,3/3] Input: xen-kbdfront - allow better run-time configuration

Commit Message

Oleksandr Andrushchenko June 12, 2018, 7:48 a.m. UTC

From: Oleksandr Andrushchenko <[e-mail]>

It is now only possible to control if multi-touch virtual device
is created or not (via the corresponding XenStore entries),
but keyboard and pointer devices are always created.
In some cases this is not desirable. For example, if virtual
keyboard device is exposed to Android then the latter won't
automatically show on-screen keyboard as it expects that a
physical keyboard device can be used for typing.

Utilize keyboard and pointer device XenStore feature fields to
configure which virtual devices are created:
 - set "feature-disable-keyboard" to 1 if no keyboard device
   needs to be created
 - set "feature-disable-pointer" to 1 if no pointer device
   needs to be created
Keep old behavior by default.

Signed-off-by: Oleksandr Andrushchenko <[e-mail]>
Suggested-by: Andrii Chepurnyi <[e-mail]>
Tested-by: Andrii Chepurnyi <[e-mail]>
---
 drivers/input/misc/xen-kbdfront.c | 177 ++++++++++++++++++------------
 1 file changed, 106 insertions(+), 71 deletions(-)

Comments

Jürgen Groß June 12, 2018, 1:50 p.m. UTC | #1

On 12/06/18 09:48, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <[e-mail]>
> 
> It is now only possible to control if multi-touch virtual device
> is created or not (via the corresponding XenStore entries),
> but keyboard and pointer devices are always created.
> In some cases this is not desirable. For example, if virtual
> keyboard device is exposed to Android then the latter won't
> automatically show on-screen keyboard as it expects that a
> physical keyboard device can be used for typing.
> 
> Utilize keyboard and pointer device XenStore feature fields to
> configure which virtual devices are created:
>  - set "feature-disable-keyboard" to 1 if no keyboard device
>    needs to be created
>  - set "feature-disable-pointer" to 1 if no pointer device
>    needs to be created
> Keep old behavior by default.
> 
> Signed-off-by: Oleksandr Andrushchenko <[e-mail]>
> Suggested-by: Andrii Chepurnyi <[e-mail]>
> Tested-by: Andrii Chepurnyi <[e-mail]>

Reviewed-by: Juergen Gross <[e-mail]>


Juergen
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Dmitry Torokhov June 12, 2018, 10:07 p.m. UTC | #2

On Tue, Jun 12, 2018 at 10:48:56AM +0300, Oleksandr Andrushchenko wrote:
>  
> +	if (!(with_kbd | with_ptr | with_mtouch)) {

I changed this to logical "OR" and applied, thank you.

> +		ret = -ENXIO;
> +		goto error;
> +	}
> +
>  	ret = xenkbd_connect_backend(dev, info);
>  	if (ret < 0)
>  		goto error;
> -- 
> 2.17.1
>

Oleksandr Andrushchenko June 13, 2018, 5:47 a.m. UTC | #3

On 06/13/2018 01:07 AM, Dmitry Torokhov wrote:
> On Tue, Jun 12, 2018 at 10:48:56AM +0300, Oleksandr Andrushchenko wrote:
>>   
>> +	if (!(with_kbd | with_ptr | with_mtouch)) {
> I changed this to logical "OR" and applied, thank you.
Yes, that's better, thank you
>> +		ret = -ENXIO;
>> +		goto error;
>> +	}
>> +
>>   	ret = xenkbd_connect_backend(dev, info);
>>   	if (ret < 0)
>>   		goto error;
>> -- 
>> 2.17.1
>>

--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
index 92d739649022..f50fba1962ec 100644
--- a/drivers/input/misc/xen-kbdfront.c
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -63,6 +63,9 @@  static void xenkbd_disconnect_backend(struct xenkbd_info *);
 static void xenkbd_handle_motion_event(struct xenkbd_info *info,
 				       struct xenkbd_motion *motion)
 {
+	if (unlikely(!info->ptr))
+		return;
+
 	input_report_rel(info->ptr, REL_X, motion->rel_x);
 	input_report_rel(info->ptr, REL_Y, motion->rel_y);
 	if (motion->rel_z)
@@ -73,6 +76,9 @@  static void xenkbd_handle_motion_event(struct xenkbd_info *info,
 static void xenkbd_handle_position_event(struct xenkbd_info *info,
 					 struct xenkbd_position *pos)
 {
+	if (unlikely(!info->ptr))
+		return;
+
 	input_report_abs(info->ptr, ABS_X, pos->abs_x);
 	input_report_abs(info->ptr, ABS_Y, pos->abs_y);
 	if (pos->rel_z)
@@ -97,6 +103,9 @@  static void xenkbd_handle_key_event(struct xenkbd_info *info,
 		return;
 	}
 
+	if (unlikely(!dev))
+		return;
+
 	input_event(dev, EV_KEY, key->keycode, value);
 	input_sync(dev);
 }
@@ -192,7 +201,7 @@  static int xenkbd_probe(struct xenbus_device *dev,
 				  const struct xenbus_device_id *id)
 {
 	int ret, i;
-	unsigned int abs, touch;
+	bool with_mtouch, with_kbd, with_ptr;
 	struct xenkbd_info *info;
 	struct input_dev *kbd, *ptr, *mtouch;
 
@@ -211,93 +220,114 @@  static int xenkbd_probe(struct xenbus_device *dev,
 	if (!info->page)
 		goto error_nomem;
 
-	/* Set input abs params to match backend screen res */
-	abs = xenbus_read_unsigned(dev->otherend,
-				   XENKBD_FIELD_FEAT_ABS_POINTER, 0);
-	ptr_size[KPARAM_X] = xenbus_read_unsigned(dev->otherend,
-						  XENKBD_FIELD_WIDTH,
-						  ptr_size[KPARAM_X]);
-	ptr_size[KPARAM_Y] = xenbus_read_unsigned(dev->otherend,
-						  XENKBD_FIELD_HEIGHT,
-						  ptr_size[KPARAM_Y]);
-	if (abs) {
-		ret = xenbus_write(XBT_NIL, dev->nodename,
-				   XENKBD_FIELD_REQ_ABS_POINTER, "1");
-		if (ret) {
-			pr_warn("xenkbd: can't request abs-pointer\n");
-			abs = 0;
-		}
-	}
+	/*
+	 * The below are reverse logic, e.g. if the feature is set, then
+	 * do not expose the corresponding virtual device.
+	 */
+	with_kbd = !xenbus_read_unsigned(dev->otherend,
+					 XENKBD_FIELD_FEAT_DSBL_KEYBRD, 0);
+
+	with_ptr = !xenbus_read_unsigned(dev->otherend,
+					 XENKBD_FIELD_FEAT_DSBL_POINTER, 0);
 
-	touch = xenbus_read_unsigned(dev->otherend,
-				     XENKBD_FIELD_FEAT_MTOUCH, 0);
-	if (touch) {
+	/* Direct logic: if set, then create multi-touch device. */
+	with_mtouch = xenbus_read_unsigned(dev->otherend,
+					   XENKBD_FIELD_FEAT_MTOUCH, 0);
+	if (with_mtouch) {
 		ret = xenbus_write(XBT_NIL, dev->nodename,
 				   XENKBD_FIELD_REQ_MTOUCH, "1");
 		if (ret) {
 			pr_warn("xenkbd: can't request multi-touch");
-			touch = 0;
+			with_mtouch = 0;
 		}
 	}
 
 	/* keyboard */
-	kbd = input_allocate_device();
-	if (!kbd)
-		goto error_nomem;
-	kbd->name = "Xen Virtual Keyboard";
-	kbd->phys = info->phys;
-	kbd->id.bustype = BUS_PCI;
-	kbd->id.vendor = 0x5853;
-	kbd->id.product = 0xffff;
-
-	__set_bit(EV_KEY, kbd->evbit);
-	for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
-		__set_bit(i, kbd->keybit);
-	for (i = KEY_OK; i < KEY_MAX; i++)
-		__set_bit(i, kbd->keybit);
-
-	ret = input_register_device(kbd);
-	if (ret) {
-		input_free_device(kbd);
-		xenbus_dev_fatal(dev, ret, "input_register_device(kbd)");
-		goto error;
+	if (with_kbd) {
+		kbd = input_allocate_device();
+		if (!kbd)
+			goto error_nomem;
+		kbd->name = "Xen Virtual Keyboard";
+		kbd->phys = info->phys;
+		kbd->id.bustype = BUS_PCI;
+		kbd->id.vendor = 0x5853;
+		kbd->id.product = 0xffff;
+
+		__set_bit(EV_KEY, kbd->evbit);
+		for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
+			__set_bit(i, kbd->keybit);
+		for (i = KEY_OK; i < KEY_MAX; i++)
+			__set_bit(i, kbd->keybit);
+
+		ret = input_register_device(kbd);
+		if (ret) {
+			input_free_device(kbd);
+			xenbus_dev_fatal(dev, ret,
+					 "input_register_device(kbd)");
+			goto error;
+		}
+		info->kbd = kbd;
 	}
-	info->kbd = kbd;
 
 	/* pointing device */
-	ptr = input_allocate_device();
-	if (!ptr)
-		goto error_nomem;
-	ptr->name = "Xen Virtual Pointer";
-	ptr->phys = info->phys;
-	ptr->id.bustype = BUS_PCI;
-	ptr->id.vendor = 0x5853;
-	ptr->id.product = 0xfffe;
-
-	if (abs) {
-		__set_bit(EV_ABS, ptr->evbit);
-		input_set_abs_params(ptr, ABS_X, 0, ptr_size[KPARAM_X], 0, 0);
-		input_set_abs_params(ptr, ABS_Y, 0, ptr_size[KPARAM_Y], 0, 0);
-	} else {
-		input_set_capability(ptr, EV_REL, REL_X);
-		input_set_capability(ptr, EV_REL, REL_Y);
-	}
-	input_set_capability(ptr, EV_REL, REL_WHEEL);
+	if (with_ptr) {
+		unsigned int abs;
+
+		/* Set input abs params to match backend screen res */
+		abs = xenbus_read_unsigned(dev->otherend,
+					   XENKBD_FIELD_FEAT_ABS_POINTER, 0);
+		ptr_size[KPARAM_X] = xenbus_read_unsigned(dev->otherend,
+							  XENKBD_FIELD_WIDTH,
+							  ptr_size[KPARAM_X]);
+		ptr_size[KPARAM_Y] = xenbus_read_unsigned(dev->otherend,
+							  XENKBD_FIELD_HEIGHT,
+							  ptr_size[KPARAM_Y]);
+		if (abs) {
+			ret = xenbus_write(XBT_NIL, dev->nodename,
+					   XENKBD_FIELD_REQ_ABS_POINTER, "1");
+			if (ret) {
+				pr_warn("xenkbd: can't request abs-pointer\n");
+				abs = 0;
+			}
+		}
 
-	__set_bit(EV_KEY, ptr->evbit);
-	for (i = BTN_LEFT; i <= BTN_TASK; i++)
-		__set_bit(i, ptr->keybit);
+		ptr = input_allocate_device();
+		if (!ptr)
+			goto error_nomem;
+		ptr->name = "Xen Virtual Pointer";
+		ptr->phys = info->phys;
+		ptr->id.bustype = BUS_PCI;
+		ptr->id.vendor = 0x5853;
+		ptr->id.product = 0xfffe;
+
+		if (abs) {
+			__set_bit(EV_ABS, ptr->evbit);
+			input_set_abs_params(ptr, ABS_X, 0,
+					     ptr_size[KPARAM_X], 0, 0);
+			input_set_abs_params(ptr, ABS_Y, 0,
+					     ptr_size[KPARAM_Y], 0, 0);
+		} else {
+			input_set_capability(ptr, EV_REL, REL_X);
+			input_set_capability(ptr, EV_REL, REL_Y);
+		}
+		input_set_capability(ptr, EV_REL, REL_WHEEL);
 
-	ret = input_register_device(ptr);
-	if (ret) {
-		input_free_device(ptr);
-		xenbus_dev_fatal(dev, ret, "input_register_device(ptr)");
-		goto error;
+		__set_bit(EV_KEY, ptr->evbit);
+		for (i = BTN_LEFT; i <= BTN_TASK; i++)
+			__set_bit(i, ptr->keybit);
+
+		ret = input_register_device(ptr);
+		if (ret) {
+			input_free_device(ptr);
+			xenbus_dev_fatal(dev, ret,
+					 "input_register_device(ptr)");
+			goto error;
+		}
+		info->ptr = ptr;
 	}
-	info->ptr = ptr;
 
 	/* multi-touch device */
-	if (touch) {
+	if (with_mtouch) {
 		int num_cont, width, height;
 
 		mtouch = input_allocate_device();
@@ -346,6 +376,11 @@  static int xenkbd_probe(struct xenbus_device *dev,
 		info->mtouch = mtouch;
 	}
 
+	if (!(with_kbd | with_ptr | with_mtouch)) {
+		ret = -ENXIO;
+		goto error;
+	}
+
 	ret = xenkbd_connect_backend(dev, info);
 	if (ret < 0)
 		goto error;