Linux Begins To Support Windows 8 Multi-Touch

The Linux 3.8 kernel is beginning work on supporting Microsoft's Windows 8 multi-touch protocol.

The HID (Human Interface Device) pull for the Linux 3.8 merge window was submitted and taken today by Linus Torvalds. One of the prominent additions to the Linux 3.8 HID support is working on the Windows 8 multi-touch protocol support. The changes with the Windows 8 multi-touch include:

Support T and C for win8 devices - "Win8 input specification clarifies the X and Y sent by devices. It distincts the position where the user wants to Touch (T) from the center of the ellipsoide (C). This patch enable supports for this distinction in hid-multitouch. We recognize Win8 certified devices from their vendor feature 0xff0000c5 where Microsoft put a signed blob in the report to check if the device passed the certification."

hid-multitouch: fix Win 8 protocol - "Win 8 specification is much more precise than the Win 7 one.
Moreover devices that need to take certification must be submitted to Microsoft. The result is a better protocol support and we can rely on that to skip all the messy tests we used to do. The protocol specify the fact that each valid touch must be reported within a frame, and that the release touch coordinate must be the same than the last known touch. So we can use the always_valid quirk and dismiss reports when we touch coordiante do not follow this rule."

This Windows 8 multi-touch work for the Linux kernel was done by Benjamin Tissoires.

Also worthy of calling attention to with this HID pull is support for HID over the I2C bus, an ION iCade driver, and support for new Roccat devices. The Roccat work for Linux 3.8 includes support for the Roccat Lua gaming mouse, reading out the Kone Plus sensor register data, support for the Kone XTD mouse, Savu/Kone Plus device reset support, and cleaning up various other Roccat driver bits.

Roccat is worthwhile for being acknowledged for since they are one of the few gaming peripheral companies that at the moment officially supports Linux. Most of the leading game peripheral vendors (keyboard, mouse, joystick, etc) don't officially support Linux drivers/user-space software at this time and leave it up to the community and independent users for assembling the support for these gaming products. Fortunately, in 2013, we're likely to see a dramatic shift in this area as gaming peripheral vendors begin to become interested by Valve's Linux-based Steam gaming console where Linux support will obviously be mandated.

The Linux 3.8 HID pull request can be found on the kernel mailing list.