On Thu, Oct 27, 2016 at 4:19 PM, Dmitry Torokhov
[off-list ref] wrote:

On Thu, Oct 27, 2016 at 02:31:13PM -0700, Roderick Colenbrander wrote:

quoted

From: Roderick Colenbrander <roderick.colenbrander@sony.com>

The input-mt driver pointer emulation from 'input_mt_sync_frame' regardless
of the flags passed in to 'input_mt_init_slots' by device drivers.

Right, because needing single-touch (pointer) emulation is not property
of device or driver but rather consumer. If we get to the point where
everything is ready to accept multi-touch (are we there yet) then we can
stop doing pointer emulation altogether.

quoted

Pointer emulation is undesired on drivers, which didn't request this
capability like the hid-sony driver for the Dualshock 4. This gamepad already
reports ABS_X / ABS_Y for gamepad stick purposes. Pointer emulation would
inject touchpad values into these sticks, which is undesired.

The driver should not be re-purposing events like that.
ABS_MT_POSITION_X and ABS_X should match.

Why doesn't driver follow Documentation/input/gamepad.txt?

The original hid-sony code and the multitouch handling code for the Dualshock 4
were written by the community. We are stepping in to make the hid-sony driver
properly handle the Dualshock 4.
The driver doesn't fully follow the gamepad spec yet, which we will
try to improve. At
least the left analog stick is reported as ABS_X and ABS_Y already,
but the buttons
are inconsistent and right stick is wrong as well.
While it would be great to conform to the spec, the conflict with
multitouch would still
exist as the Dualshock 4 has both analog sticks and a multitouch touchpad.

Disabling the pointer emulation feature avoids the conflict. This
issue was only exposed
recently by adding of the input_mt_sync_frame call as recommended by Benjamin as
part of some improvements we did for touchpad handling in hid-sony.

quoted

This patch checks the flags INPUT_MT_POINTER / INPUT_MT_DIRECT from within
input_mt_sync_frame to only allow pointer emulation when the feature was
requested by the driver as the flags were set in input_mt_init_slots.
---
 drivers/input/input-mt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index a1bbec9..30c8128 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c

@@ -305,7 +305,8 @@ void input_mt_sync_frame(struct input_dev *dev)
      if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
              use_count = true;

-     input_mt_report_pointer_emulation(dev, use_count);
+     if (mt->flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT))
+             input_mt_report_pointer_emulation(dev, use_count);

      mt->frame++;
 }
--

2.7.4

Thanks.

--
Dmitry

Thanks,

-- 
Roderick Colenbrander
Senior Manager of Software Engineering
Gaikai, a Sony Interactive Entertainment Company
roderick@gaikai.com