Some touchscreen support..

Pekka Paalanen ppaalanen at
Mon Nov 11 00:42:43 PST 2013

On Sun, 10 Nov 2013 16:09:21 +0200
Oskari Rauta <oskari.rauta at> wrote:

> Raspberry Pi version doesn't support currently udev properties, I once modified evdev, so it accepted touchscreen calibration values from udev..

Really? I see the code reads ID_SEAT. How does that not work for
ignoring a device?

Granted, I have never had to play with seat designations.

This also reminds me we still haven't ported the rpi backend to use the
shared udev input code in udev-seat.c.


> But that wasn't helpful with my touchscreen;; So I didn't make that a patch.. Complete ignoring of the device-- Well doing that through the udev
> sounds good, but cursor-disabled.. That can't be in udev env vars.. I'll think about what you said- Maybe I'll work on a patch later..
> On 8.11.2013, at 11:41, Pekka Paalanen <ppaalanen at> wrote:
> > On Thu, 7 Nov 2013 17:46:34 +0200
> > Oskari Rauta <oskari.rauta at> wrote:
> > 
> >> Hi.
> >> 
> >> I plan to use weston on Raspberry Pi with a touchscreen. I purchased
> >> a touchscreen that sports a eGalax touch digitizer. It seems not to
> >> be properly supported by Weston or.. Actually with nearly with any
> >> software, except tslib. Although even tslib didn't support my
> >> version(0x0100) before I patched it. EETI provides binary-only
> >> drivers for x86(32&64), arm and mips, but I wasn't able to get the
> >> driver to work - and when I checked out internet for reports, people
> >> who had got those drivers to work, were un-satisfied..
> >> 
> >> I found a project opengalax, which I forked and modified to support
> >> tslib instead of eGalax on serial. It works very good. As TSLIB
> >> doesn't support multiple simultaneous touches, gestures, like
> >> pinching - are not possible. Virtual input device created works great
> >> (after tslib's calibration) with weston- but weston tryies to access
> >> touchscreen through 2 devices, original and through virtual - I
> >> wanted weston to ignore this real device, so I made a patch to
> >> weston, that adds a new option to configuration:
> >> 
> >> [input-method]
> >> ignored=eGalax Inc. USB TouchController
> >> 
> >> And if this is set, it compares it to device name, and skips it. If
> >> nothing else, atleast there's one device not to monitor..
> > 
> > Hmm, maybe you could use udev properties somehow instead. Weston has a
> > mechanism to get devices belonging to a seat, and if you mark the device
> > to belong in a different seat in udev, Weston should ignore it. I can't
> > give any specific instructions off hand, though. There might be also
> > other udev features that the seat designation, perhaps.
> > 
> >> Second thing.. As I am using a touchscreen.. I wanted to disable
> >> mouse cursor. I patched weston some more to add option [shell]
> >> cursor-disabled=true
> >> 
> >> - if this is set, mouse cursor isn't drawn.
> >> 
> >> My fork of opengalax is not yet publicly available, but patch to what
> >> I described is included in this message.
> > 
> > The mouse cursor sounds like your touchscreen is detected as a pointer
> > device instead of a touchscreen. AFAIK, Weston does not draw cursors
> > for touchscreens. You can check the detection result in the weston log.
> > 
> > I suspect the virtual evdev device is not set up properly to act only
> > as touch input. I guess it is (was?) common to have single-touch devices
> > emulate a mouse instead of a touch device, so that you wouldn't need
> > any changes in other software, so it might even be deliberate that your
> > touch device is detected as a pointer device and gets a cursor.
> > Needless to say, emulating a mouse like that is full of fail. So,
> > checking how your virtual evdev device looks like is one thing.
> > 
> > 
> > Thanks,
> > pq

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