Re: ELAN Touchscreen regression in recent 3.12 rc's? (USB)

From: Nikolai Kondrashov
Date: Wed Oct 30 2013 - 04:37:44 EST

Hi AceLan,

On 10/30/2013 03:41 AM, AceLan Kao wrote:
It's hard to believe that those quirks will lead to the problem.
And actually, there are 4 new commits introduced to -rc7, and 3 of
them are quirks.

% git log --pretty=oneline v3.12-rc6..v3.12-rc7 drivers/hid
86b84167d4e67372376a57ea9955c5d53dae232f HID: wiimote: add LEGO-wiimote VID
ad0e669b922c7790182cf19f8015b30e23ad9499 HID: Fix unit exponent parsing again
684524d35fe8d13be1f2649633e43bd02c96c695 HID: usbhid: quirk for SiS Touchscreen
8171a67d587a09e14a4949a81e070345fedcf410 HID: usbhid: quirk for
Synaptics Large Touchccreen

CC'd Nikolai, since his commit changes the protocol.

My change is very unlikely to produce such problems. It changes calculation of
axes resolution at the time the report descriptor is processed. The results of
the calculation are not used by the kernel, AFAIK, but only by userspace
drivers. The results should not be used to affect the interactions with the
device, but only the interpretation of the reports (again, in userspace), and
even that is barely done currently.

Please try reverting that particular commit and see if it affects the

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