[Bug 625511] [NEW] Obsolete quirk prevents multitouch module for eGalax touchscreen from working

[Plippo]

Public bug reported:

In the Maverick Kernel (tested with 2.6.35-19) the eGalax/DWAV
touchscreen (USB ID 0eef:480d) found in the Eee PC T101MT doesn't send
multitouch events although the correct module hid_egalax is included in
the Kernel. The reason is that the MULTI_INPUT quirk is still used for
this device although it is no longer needed, and it prevents the module
from working.

Steps to reproduce:
Start Ubuntu 10.10 on an Eee PC T101MT with eGalax touchscreen. Check xinput --list to find out that the screen is listed twice. Run evtest to find out that four device nodes (/dev/input/event6 ... /dev/input/event9) are created for the device. Only one of them produces events, and they are only single touch events. The other nodes produce no events at all. None produces multitouch events.

Reason:
In drivers/hid/usbhid/hid-quirks.c , you find the line
{ USB_VENDOR_ID_DWAV, USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH, HID_QUIRK_MULTI_INPUT }
which causes the MULTI_INPUT quirk to be added to the device, which prevents the hid_egalax module from working and thus only the quirky default handling of the touchscreen is applied.

Fix:
Remove this line from hid-quirks.c using the attached patch; Now hid_egalax manages the screen: it appears only once in xinput --list, only creates one device node which delivers single touch and multitouch events, as expected.


One problem with this fix though: Because of a bug in the hid_egalax module, the screen assumes a wrong range for the coordinate axes when in multitouch mode. I have created a separate patch for this, shall I attach it to this bug (because otherwise the screen doesn't work when this fix is applied) or create a new bug for this?

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

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Obsolete quirk prevents multitouch module for eGalax touchscreen from working
https://bugs.launchpad.net/bugs/625511
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