[PATCH] Fix for problems with eGalax/DWAV multi-touch-screen

[PATCH] Fix for problems with eGalax/DWAV multi-touch-screen

[Philipp Merkel]

This patch fixes three problems with the eGalax/DWAV multi-touch
screen found in the Eee PC T101MT:

1) While there is a dedicated multitouch driver for the screen
   (hid-egalax.c), the MULTI_INPUT quirk is also applied, preventing
   the hid-egalax driver from working. This patch removes the quirk
   so the hid-egalax driver can handle the device correctly.
2) The x and y coordinates sent by the screen in multi-touch mode are
   shifted by three bits from the events sent in single-touch mode, thus
   the coordinates are out of range, leading to the pointer being stuck
   in the bottom-right corner if no additional calibration is applied
   (e.g. in the X evdev driver). This patch shifts the coordinates back.
   This does not decrease accuracy as the last three bits of the "wrong"
   coordinates are always 0.
3) Only multi-touch pressure events are sent, single touch emulation is
   missing pressure information. This patch adds single-touch
   ABS_PRESSURE events. 

Signed-off-by: Philipp Merkel <mail@philmerk.de>

diff -ru a/drivers/hid/usbhid/hid-quirks.c b/drivers/hid/usbhid/hid-quirks.c
--- a/drivers/hid/usbhid/hid-quirks.c	2010-08-27 18:41:20.000000000 +0200
+++ b/drivers/hid/usbhid/hid-quirks.c	2010-08-27 18:42:07.000000000 +0200
@@ -33,7 +33,6 @@
 	{ USB_VENDOR_ID_AASHIMA, USB_DEVICE_ID_AASHIMA_PREDATOR, HID_QUIRK_BADPAD },
 	{ USB_VENDOR_ID_ALPS, USB_DEVICE_ID_IBM_GAMEPAD, HID_QUIRK_BADPAD },
 	{ USB_VENDOR_ID_CHIC, USB_DEVICE_ID_CHIC_GAMEPAD, HID_QUIRK_BADPAD },
-	{ USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH, HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_MOJO, USB_DEVICE_ID_RETRO_ADAPTER, HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_DRIVING, HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_HAPP, USB_DEVICE_ID_UGCI_FLYING, HID_QUIRK_BADPAD | HID_QUIRK_MULTI_INPUT },

diff -ru a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
--- a/drivers/hid/hid-egalax.c	2010-08-27 18:48:17.851442000 +0200
+++ b/drivers/hid/hid-egalax.c	2010-08-29 11:26:02.385106000 +0200
@@ -31,7 +31,7 @@
 	bool first;		/* is this the first finger in the frame? */
 	bool valid;		/* valid finger data, or just placeholder? */
 	bool activity;		/* at least one active finger previously? */
-	__u16 lastx, lasty;	/* latest valid (x, y) in the frame */
+	__u16 lastx, lasty, lastz;	/* latest valid (x, y, z) in the frame */
 };
 
 static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
@@ -79,6 +79,10 @@
 		case HID_DG_TIPPRESSURE:
 			hid_map_usage(hi, usage, bit, max,
 					EV_ABS, ABS_MT_PRESSURE);
+			/* touchscreen emulation */
+			input_set_abs_params(hi->input, ABS_PRESSURE,
+						field->logical_minimum,
+						field->logical_maximum, 0, 0);
 			return 1;
 		}
 		return 0;
@@ -109,8 +113,8 @@
 	if (td->valid) {
 		/* emit multitouch events */
 		input_event(input, EV_ABS, ABS_MT_TRACKING_ID, td->id);
-		input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x);
-		input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y);
+		input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x >> 3);
+		input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y >> 3);
 		input_event(input, EV_ABS, ABS_MT_PRESSURE, td->z);
 
 		input_mt_sync(input);
@@ -121,6 +125,7 @@
 		 */
 		td->lastx = td->x;
 		td->lasty = td->y;
+		td->lastz = td->z;
 	}
 
 	/*
@@ -129,8 +134,9 @@
 	 * the oldest on the panel, the one we want for single touch
 	 */
 	if (!td->first && td->activity) {
-		input_event(input, EV_ABS, ABS_X, td->lastx);
-		input_event(input, EV_ABS, ABS_Y, td->lasty);
+		input_event(input, EV_ABS, ABS_X, td->lastx >> 3);
+		input_event(input, EV_ABS, ABS_Y, td->lasty >> 3);
+ 		input_event(input, EV_ABS, ABS_PRESSURE, td->lastz);
 	}
 
 	if (!td->valid) {

Re: [PATCH] Fix for problems with eGalax/DWAV multi-touch-screen

[Stéphane Chatty]

Le 14 sept. 10 à 17:08, Philipp Merkel a écrit :


> 3) Only multi-touch pressure events are sent, single touch  
> emulation is
>    missing pressure information. This patch adds single-touch
>    ABS_PRESSURE events.
>
Oops, thx for the fix.

>
> 1) While there is a dedicated multitouch driver for the screen
>    (hid-egalax.c), the MULTI_INPUT quirk is also applied, preventing
>    the hid-egalax driver from working. This patch removes the quirk
>    so the hid-egalax driver can handle the device correctly.

No opinion here, I'm not comfortable with MULTI_INPUT and multitouch  
(too much variability from one device to another).

> 2) The x and y coordinates sent by the screen in multi-touch mode are
>    shifted by three bits from the events sent in single-touch mode,  
> thus
>    the coordinates are out of range, leading to the pointer being  
> stuck
>    in the bottom-right corner if no additional calibration is applied
>    (e.g. in the X evdev driver). This patch shifts the coordinates  
> back.
>    This does not decrease accuracy as the last three bits of the  
> "wrong"
>    coordinates are always 0.

Mmm. This would be a bug in the firmware? I'll notify the eGalax  
folks. Anyway, if there's a bug we must fix it. But the driver was  
(probably too quickly) registered for another eGalax product with a  
different protocol: 0x0eef:0x720c (the one in the Joojoo). Can  
someone check if the fix applies to this product as well? Otherwise  
we'll have to devise a solution.

St.



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Re: [PATCH] Fix for problems with eGalax/DWAV multi-touch-screen

[Philipp Merkel]

> > 1) While there is a dedicated multitouch driver for the screen
> >    (hid-egalax.c), the MULTI_INPUT quirk is also applied, preventing
> >    the hid-egalax driver from working. This patch removes the quirk
> >    so the hid-egalax driver can handle the device correctly.
> 
> No opinion here, I'm not comfortable with MULTI_INPUT and multitouch  
> (too much variability from one device to another).
I can only tell you what I experienced: Before the hid_egalax driver,
one had to use the MULTI_INPUT quirk in order to make the device work as
a single-touch screen, otherwise the coordinates were sent for the wrong
axes. But now with hid_egalax handling the device, the MULTI_INPUT quirk
is of no use any more for this device and instead seems to prevent
hid_egalax from working (it's loaded, but doesn't seem to handle the
device as no multitouch events are sent). So it's a leftover from before
hid_egalax and can safely be removed.

> > 2) The x and y coordinates sent by the screen in multi-touch mode are
> >    shifted by three bits from the events sent in single-touch mode,  
> > thus
> >    the coordinates are out of range, leading to the pointer being  
> > stuck
> >    in the bottom-right corner if no additional calibration is applied
> >    (e.g. in the X evdev driver). This patch shifts the coordinates  
> > back.
> >    This does not decrease accuracy as the last three bits of the  
> > "wrong"
> >    coordinates are always 0.
> 
> Mmm. This would be a bug in the firmware? I'll notify the eGalax  
> folks. Anyway, if there's a bug we must fix it. But the driver was  
> (probably too quickly) registered for another eGalax product with a  
> different protocol: 0x0eef:0x720c (the one in the Joojoo). Can  
> someone check if the fix applies to this product as well? Otherwise  
> we'll have to devise a solution.
I don't have a Joojoo, but as its touch screen seems to be quite
different, it's probably necessary to distinguish the devices in the
driver anyway. At least from what I know from other T101MT users, all
screens with the id 0x0eef:0x480d seem to suffer from this problem.

Another possibility would maybe be the following: If the coordinates of
the first touch after loading the driver are within the range, the
device is set to "Normal" mode and all coordinates are passed as they
are. If the first touch is out of range, the device is set to "Quirks"
mode and all coordinates are shifted by three bits. This way, the driver
would continue working even if the bug in the firmware was corrected for
new devices with the same ID. It would be no problem to adapt my patch
this way.

For me, the values are as follows: In the HID descriptor, a range of
0-4095 is given for the X and Y axes. So the only situation in which the
above solution would not switch the mode correctly would be if the first
touch after loading the driver would be in the very top-left corner,
with an X and Y coordinate between 0 and 4, as in this case it would be
reported as <=4000 and thus not registered as being out of range. This
is very unlikely as at least for my screen, one has to press the stylus
with force into the corner in order to get such coordinates, which
probably no user will do just after turning on his machine...

Re: [PATCH] Fix for problems with eGalax/DWAV multi-touch-screen

[Jiri Kosina]

On Mon, 20 Sep 2010, Stéphane Chatty wrote:

> > 3) Only multi-touch pressure events are sent, single touch emulation is
> >   missing pressure information. This patch adds single-touch
> >   ABS_PRESSURE events.
> > 
> Oops, thx for the fix.

Stephane, can I consider this being your Acked-by: for the whole patch?

Thanks,

-- 
Jiri Kosina
SUSE Labs, Novell Inc.
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Re: [PATCH] Fix for problems with eGalax/DWAV multi-touch-screen

[Stéphane Chatty]

Le 21 sept. 10 à 16:06, Jiri Kosina a écrit :

> On Mon, 20 Sep 2010, Stéphane Chatty wrote:
>
>>> 3) Only multi-touch pressure events are sent, single touch  
>>> emulation is
>>>   missing pressure information. This patch adds single-touch
>>>   ABS_PRESSURE events.
>>>
>> Oops, thx for the fix.
>
> Stephane, can I consider this being your Acked-by: for the whole  
> patch?

Well, there's still the issue of the 0eef:72xx series that might be  
disrupted by the patch. We can decide to remove that series from the  
list of supported devices, but it would be good to check first  
whether these panels have the same issue or not. If they do, we can  
apply the patch without second thoughts. If they don't, we should  
probably remove them and write another driver. I have asked feedback  
from an author of PyMT who owns a Joojoo.

Cheers,

St. --
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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Henrik Rydberg]

On 09/14/2010 05:08 PM, Philipp Merkel wrote:

> This patch fixes three problems with the eGalax/DWAV multi-touch
> screen found in the Eee PC T101MT:
> 
> 1) While there is a dedicated multitouch driver for the screen
>    (hid-egalax.c), the MULTI_INPUT quirk is also applied, preventing
>    the hid-egalax driver from working. This patch removes the quirk
>    so the hid-egalax driver can handle the device correctly.
> 2) The x and y coordinates sent by the screen in multi-touch mode are
>    shifted by three bits from the events sent in single-touch mode, thus
>    the coordinates are out of range, leading to the pointer being stuck
>    in the bottom-right corner if no additional calibration is applied
>    (e.g. in the X evdev driver). This patch shifts the coordinates back.
>    This does not decrease accuracy as the last three bits of the "wrong"
>    coordinates are always 0.
> 3) Only multi-touch pressure events are sent, single touch emulation is
>    missing pressure information. This patch adds single-touch
>    ABS_PRESSURE events. 
> 
> Signed-off-by: Philipp Merkel <mail@philmerk.de>
> 


This is a late reply to the whole thread.

I have looked at the joojoo (0eef:720c), and constructed a driver for it using
MT slots. If would be great if it could be merged with the 0eef:480d in the
hid-egalax driver, but there are some things to work out before that can happen.
Here are some observations from the joojoo:

1) The HID report says the x/y coordinates are in the 4096 range, but in
actuality, they are 32kx32k it seems.

2) Reports fingers serially using slots, and there is *no* message indicating a
frame. As Stephane pointed out earlier.

3) Reports x, y and pressure (emulated most likely, since the device is capacitive).

4) Very fast - below 5 ms between completions from preliminary measurements.

5) Only two fingers, but of good quality.

Because of 2), the MT slots protocol is not only suitable, but required unless
additional complicating logic is introduced.

Philipp, Stephane, if you are interested in testing out the driver on the
0eff:480d, please let me know (off list), and we should hopefully be able to
find a merge.

Cheers,
Henrik

Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Stéphane Chatty]

Le 28 sept. 10 à 21:32, Henrik Rydberg a écrit :

>
> Philipp, Stephane, if you are interested in testing out the driver  
> on the
> 0eff:480d, please let me know (off list), and we should hopefully  
> be able to
> find a merge.
>


I don't have an eGalax device :-)

By the way, since you apparently have access to a Joojoo and I did  
not get any response from any Joojoo owner, can you tell us whether  
it exhibits the bogus Xs and Ys that Philipp has observed? It would  
be consistent with the range inconsistency that you have observed.

St.

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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Henrik Rydberg]

On 09/28/2010 09:43 PM, Stéphane Chatty wrote:

> 
> Le 28 sept. 10 à 21:32, Henrik Rydberg a écrit :
> 
>>
>> Philipp, Stephane, if you are interested in testing out the driver on the
>> 0eff:480d, please let me know (off list), and we should hopefully be able to
>> find a merge.
>>
> 
> 
> I don't have an eGalax device :-)
> 
> By the way, since you apparently have access to a Joojoo and I did not get any
> response from any Joojoo owner, can you tell us whether it exhibits the bogus Xs
> and Ys that Philipp has observed? It would be consistent with the range
> inconsistency that you have observed.


Yes, since (4k << 3) == 32k, I believe we are looking at the same behavior on
both devices.

Henrik
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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Philipp Merkel]

Stéphane Chatty wrote:
> By the way, since you apparently have access to a Joojoo and I did  
> not get any response from any Joojoo owner, can you tell us whether  
> it exhibits the bogus Xs and Ys that Philipp has observed? It would  
> be consistent with the range inconsistency that you have observed.

As I wrote in my previous message (but was too slow and didn't read
yours before sending it), the problem Henrik is describing sounds
exactly like the one I experienced which is fixed by the three bit
shift.

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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Stéphane Chatty]

Le 28 sept. 10 à 21:55, Philipp Merkel a écrit :

> Stéphane Chatty wrote:
>> By the way, since you apparently have access to a Joojoo and I did
>> not get any response from any Joojoo owner, can you tell us whether
>> it exhibits the bogus Xs and Ys that Philipp has observed? It would
>> be consistent with the range inconsistency that you have observed.
>
> As I wrote in my previous message (but was too slow and didn't read
> yours before sending it), the problem Henrik is describing sounds
> exactly like the one I experienced which is fixed by the three bit
> shift.

Then we could take Philipp's fix for now, and start looking for a way  
to cross-test Henrik's proposal. Jiri, do you agree on this?

St.

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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Jiri Kosina]

On Tue, 28 Sep 2010, Stéphane Chatty wrote:

> > > By the way, since you apparently have access to a Joojoo and I did
> > > not get any response from any Joojoo owner, can you tell us whether
> > > it exhibits the bogus Xs and Ys that Philipp has observed? It would
> > > be consistent with the range inconsistency that you have observed.
> > 
> > As I wrote in my previous message (but was too slow and didn't read
> > yours before sending it), the problem Henrik is describing sounds
> > exactly like the one I experienced which is fixed by the three bit
> > shift.
> 
> Then we could take Philipp's fix for now, and start looking for a way to
> cross-test Henrik's proposal. Jiri, do you agree on this?

Sounds reasonable to me. So can I add

	Acked-by: Stéphane Chatty <chatty@enac.fr>

to Philipp's patch?

Thanks,

-- 
Jiri Kosina
SUSE Labs, Novell Inc.
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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Stéphane Chatty]

Le 1 oct. 10 à 15:32, Jiri Kosina a écrit :

> On Tue, 28 Sep 2010, Stéphane Chatty wrote:
>
>>>> By the way, since you apparently have access to a Joojoo and I did
>>>> not get any response from any Joojoo owner, can you tell us whether
>>>> it exhibits the bogus Xs and Ys that Philipp has observed? It would
>>>> be consistent with the range inconsistency that you have observed.
>>>
>>> As I wrote in my previous message (but was too slow and didn't read
>>> yours before sending it), the problem Henrik is describing sounds
>>> exactly like the one I experienced which is fixed by the three bit
>>> shift.
>>
>> Then we could take Philipp's fix for now, and start looking for a  
>> way to
>> cross-test Henrik's proposal. Jiri, do you agree on this?
>
> Sounds reasonable to me. So can I add
>
> 	Acked-by: Stéphane Chatty <chatty@enac.fr>
>
> to Philipp's patch?

Fine by me. And Henrik's solution should come soon, from what I hear.

Cheers,

St.

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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Jiri Kosina]

On Fri, 1 Oct 2010, Stéphane Chatty wrote:

> > > > > By the way, since you apparently have access to a Joojoo and I did
> > > > > not get any response from any Joojoo owner, can you tell us whether
> > > > > it exhibits the bogus Xs and Ys that Philipp has observed? It would
> > > > > be consistent with the range inconsistency that you have observed.
> > > > 
> > > > As I wrote in my previous message (but was too slow and didn't read
> > > > yours before sending it), the problem Henrik is describing sounds
> > > > exactly like the one I experienced which is fixed by the three bit
> > > > shift.
> > > 
> > > Then we could take Philipp's fix for now, and start looking for a way to
> > > cross-test Henrik's proposal. Jiri, do you agree on this?
> > 
> > Sounds reasonable to me. So can I add
> > 
> > 	Acked-by: Stéphane Chatty <chatty@enac.fr>
> > 
> > to Philipp's patch?
> 
> Fine by me. And Henrik's solution should come soon, from what I hear.

Excellent. Applied now, thanks!

-- 
Jiri Kosina
SUSE Labs, Novell Inc.
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Re: Fix for problems with eGalax/DWAV multi-touch-screen

[Philipp Merkel]

Henrik Rydberg wrote:
> I have looked at the joojoo (0eef:720c), and constructed a driver for it using
> MT slots. If would be great if it could be merged with the 0eef:480d in the
> hid-egalax driver, but there are some things to work out before that can happen.
> Here are some observations from the joojoo:
> 
> 1) The HID report says the x/y coordinates are in the 4096 range, but in
> actuality, they are 32kx32k it seems.

Thanks for testing! Okay, so the 0eef:720c also suffers from the
three-bit-shift problem my patch addresses. I think it can now be safely
applied, or what do you think, Stéphane? Getting your Acked-by?

Of course, this is only an intermediate step that will solve the
problems of the 0eef:480d and correct the coordinates of the 0eef:720c,
but note solve the multitouch prolem on the latter. I would be glad to
test your driver on the 0eef:480d, Henrik, I will send you (and
Stéphane) a message off-list about that.

Best Regards
Philipp

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