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Re: libmtdev and XT2
On Fri, Apr 22, 2011 at 4:10 PM, Paolo Olivo <olivopaolo@xxxxxxxxxx> wrote:
> Hello everyone,
> I am developing a mt toolkit, which I would like to interface to
> libmtdev. I am using a Dell XT2 and a 3M M2256PW touchscreen on Ubuntu
> 10.10, kernel 2.6.35-28-generic, libmtdev1.1.0.
> I started capturing mtdev events, but I found something weird. I don't
> know if they are bugs or it is simply my misunderstanding.
> First, using function "mtdev_has_mt_event" on the XT2 and passing
> ABS_MT_SLOT and ABS_MT_TRACKING_ID, in both cases it returns 0, while
> I actually receive ABS_MT_SLOT and ABS_MT_TRACKING_ID events using
> "mtdev_get". 3M is working fine.
> The second issue is about the order of the received events and I found
> a weird behavior on the XT2:
> This is a screenshot of 3M mtdev events:
> #) ev->type ev->code ev->value
> 1) 0x3 0x2f 0 SELECT SLOT 0
> 2) 0x3 0x39 -1 SET TRACKING_ID TO -1
> 3) 0x3 0x2f 1 SELECT SLOT 1
> 4) 0x3 0x35 14214 SET ABS_MT_POSITION_X
> 5) 0x3 0x36 14907 SET ABS_MT_POSITION_Y
> 6) 0x3 0x30 1207 SET ABS_MT_TOUCH_MAJOR
> 7) 0x3 0x0 14214 don't know but it has the same
> value as 4)
> 8) 0x3 0x1 14907 don't know but is has the same
> value as 5)
> 9) 0x0 0x0 0 EV_SYN
> 10) 0x3 0x35 14278 SET ABS_MT_POSITION_X
> 11) 0x3 0x36 14979 SET ABS_MT_POSITION_Y
> 12) 0x3 0x30 1172 SET ABS_MT_TOUCH_MAJOR
> 13) 0x3 0x0 14278 don't know but it has the same
> value as 10)
> 14) 0x3 0x1 14979 don't know but it has the same
> value as 11)
> 15) 0x0 0x0 0 EV_SYN
> 16) 0x3 0x39 -1 SET TRACKING_ID TO -1
> 17) 0x1 0x14a 0 don't know what it is
> 18) 0x0 0x0 0 EV_SYN
> This is a screenshot of XT2 mtdev events:
> 20) 0x3 0x0 6295 don't know but it has the
> same value as 24)
> 21) 0x3 0x1 3548 don't know but it has the
> same value as 25)
> 22) 0x3 0x2f 1 SELECT SLOT 1
> 23) 0x3 0x31 247 SET ABS_MT_TOUCH_MINOR
> 24) 0x3 0x35 6295 SET ABS_MT_POSITION_X
> 25) 0x3 0x36 3548 SET ABS_MT_POSITION_Y
> 26) 0x3 0x2f 0 SELECT SLOT 0
> 27) 0x3 0x39 -1 SET TRACKING_ID TO -1
> 28) 0x0 0x0 0 EV_SYN
> 29) 0x3 0x0 6306 don't know but it has the
> same value as 33) which will be for slot 1 BUT current slot is 0!
> 30) 0x3 0x1 3620 don't know but it has the
> same value as 34) which will be for slot 1 BUT current slot is 0!
> 31) 0x3 0x2f 1 SELECT SLOT 1
> 32) 0x3 0x34 1 SET ABS_MT_ORIENTATION
> 33) 0x3 0x35 6306 SET ABS_MT_POSITION_X
> 34) 0x3 0x36 3620 SET ABS_MT_POSITION_Y
> 35) 0x0 0x0 0 EV_SYN
> So on XT2 events type 0x03 with value 0x0 and 0x1 are sent first SLOT
> selection. Is it right?
> Does anybody know what are they?
0x3:0x0 and 0x03:0x1 are legacy non-MT events ABS_X and ABS_Y, respectively.
I'm not sure exactly how the driver chooses which contact to use for
generating these single touch events, but my guess from your snippet
is the lowest slot that happens to be on the surface.
> I hope this could be useful,
> thanks for consideration.
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