Re: eGalax touchscreen regression

From: Dmitry Torokhov
Date: Fri Apr 26 2013 - 11:39:20 EST

On Fri, Apr 26, 2013 at 06:09:05PM +0300, Artem Bityutskiy wrote:
> On Fri, 2013-04-26 at 16:59 +0200, Arnd Bergmann wrote:
> > On Wednesday 24 April 2013 12:03:13 Artem Bityutskiy wrote:
> > > On Tue, 2013-04-23 at 08:40 -0700, Dmitry Torokhov wrote:
> > > > > the eGalax driver now requires OF. For us this is a regression because
> > > > > we do not have OF:
> > > >
> > > > I see. In this case we need to come up with a platform data to pass
> > > > wakeup gpio in case platform does not support OF. irq_to_gpio() is not
> > > > supported on many platforms, causing compilation errors.
> > > >
> > > > Is the platform that you are trying to use the touchscreen upstream?
> > >
> > > OK, so this is about just a monitor with a touchscreen (Giantec high-res
> > > capacitive 11.6â LCD monitor). The touchscreen is connected to a
> > > commodity hardware via USB.
> > >
> > > So yes, the platform _is_ upstream Namely, we use just a SandyBridge
> > > PC.
> >
> > So you use a usb-to-i2c interface?
> I do not think so. The problem is that I do not have the HW, so I was
> making guesses, and it looks like this driver has nothing to do with the
> regression we've got. Sorry for the noise. We'll investigate this more
> carefully internally.

OK, so assuming you simply using USB version of eGalax device the only
recent change (3.6-rc7) was:

commit 037a833ed05a86d01ea27a2c32043b86c549be1b
Author: Forest Bond <>
Date: Tue Sep 4 20:27:37 2012 -0700

Input: usbtouchscreen - initialize eGalax devices

Certain eGalax devices expose an interface with class HID and protocol
None. Some work with usbhid and some work with usbtouchscreen, but
there is no easy way to differentiate. Sending an eGalax diagnostic
packet seems to kick them all into using the right protocol for
usbtouchscreen, so we can continue to bind them all there (as opposed to
handing some off to usbhid).

This fixes a regression for devices that were claimed by (and worked
with) usbhid prior to commit 139ebe8dc80dd74cb2ac9f5603d18fbf5cff049f
("Input: usbtouchscreen - fix eGalax HID ignoring"), which made
usbtouchscreen claim them instead. With this patch they will still be
claimed by usbtouchscreen, but they will actually report events
usbtouchscreen can understand. Note that these devices will be limited
to the usbtouchscreen feature set so e.g. dual touch features are not

I have the distinct pleasure of needing to support devices of both types
and have tested accordingly.

Signed-off-by: Forest Bond <>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>


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