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Re: USB Touch Screen support ?

On Thu, 21 May 2009, Joel Carnat wrote:

> I just modded my EeePC 701 with an "Easy to Touch" touch screen set.
> The whole new stuff seem to be recognised but now what ? :-)

more work :)

> The relevant dmesg part seem to be:
> uhidev0 at uhub5 port 1 configuration 1 interface 0
> uhidev0: HID TOUCH HID Touch Panel, rev 1.10/0.00, addr 4, iclass 3/0
> uhidev0: 3 report ids
> uhid0 at uhidev0 reportid 1: input=0, output=0, feature=21
> ums0 at uhidev0 reportid 2
> ums0: X report 0x0002 not supported

+ uhid1 at uhidev0 reportid 3: input=5, output=0, feature=0

> I read that I have to calibrate the touchscreen using some kind of
> software. I have a CD that provides Windows and Linux drivers. According
> to the dmesg, is the touch screen supported by NetBSD or do I have to
> switch to some Linux distro ?

USB HID capabilities are segmented into reports - in your case, reports 1
and 3 have no specific kernel handler and attach to uhid for userspace to
access as /dev/uhid0 and /dev/uhid1.

report 1 is a 21-byte feature report. I'm not sure, but I think this is a
way to set options on the device (aka ioctl). Perhaps relating to

report 2 is identified as a mouse input report, but the ums driver has
failed to attach - probably because it is absolute position reports rather
than differential (don't know why that would pretend to be a mouse
though). So far as I recall, the wsmouse_input() routine does accept
absolute positioning fine so its just that the ums driver does not handle

report 3 is another input report (5 bytes)

You can get more information about the reports using usbhidctl(1) to dump
the device descriptor, and perhaps the linux calibration program (if
actually required) can be converted to work.

There is also a USB touch panel driver uep(4) but that seems a hardware
specific driver, and tpctl(8) has been in tree for a long time but I don't
know if it is relevant here.  Also you might like to check the archives,
there was somebody working on a touchscreen driver last year (perhaps GSoC ?)


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