Kernel Log: Multitouch for X.org and new graphics drivers
by Thorsten Leemhuis
X-Server 1.12 will include proper support for touch screens with multitouch capabilities. All three major manufacturers of graphics hardware for PCs have released new drivers. Linux 3.0 is still being maintained even though Linux 3.1 has already been out for a few weeks.
Peter Hutterer, maintainer of the X Input Extension for X.org's X server, has submitted a patch series for review that adds support for multitouch input to the X-Server – that is, using more than one finger on a touch screen to control the user interface, which is particularly interesting for tablets. This support is realised with version 2.2 of the X Input Extension. The code will most likely soon go into the development branch of the X server, from which version 1.12 should emerge in March; that new version, in turn, will likely become part of X.org 7.7, according to rough plans.
Applications and the toolkits they use, such as GTK and Qt, will need to be updated to take full advantage of the new multitouch support; some developers are already working on the required code. A page in the X.org wiki further explains the X developers' approach; Hutterer also provides more details in a blog entry, which includes a video demonstrating how the technology is used.
Hutterer also recently released version 2.1 of Inputproto, which contains the protocol specification and header file of the X Input Extension. This version adds support for smooth scrolling and allows client programs to retrieve raw events, even when the input device is currently grabbed; the Red Hat developers provide background information in four blog entries (1, 2, 3, 4).
The developers of graphics drivers for Intel's processors and chipsets, which are mostly integrated in notebooks and desktop PCs, have put together the Intel 2011Q4 graphics package. As usual, the package is a collection of various components of the Linux graphics stack that work together well, according to the Intel developers. They point out that RC6, the technology that makes it possible to conserve quite a lot of power, is disabled by default and can be enabled with the
i915.i915_enable_rc6=1 kernel parameter; however, doing so could lead to stability problems on systems where VT-d is enabled. The new version also improves support for chips from the Ivy Bridge platform, which Intel plans to introduce next year. Intel developer Eugeni Dodonov provides much more information on the latest driver developments in a series of recently published blog posts (1, 2, 3); the slides for a presentation that Dodonov recently gave at Linuxcon Brazil are also very informative.
AMD has released version 11.12 of its proprietary Linux graphics drivers. As has been the case with AMD lately, the web site offers no information on the changes in the new version. According to a post from Phoronix, the new drivers provide early support for the recently released Red Hat Enterprise Linux 6.2. The story says that, even with the new version, members of the Phoronix forums continue to see problems with video playback and rendering errors when using Gnome 3.
In mid-December, NVIDIA released version 275.43 of its proprietary graphics drivers for x86-32/x86 and x86-64/x64, which mostly fixes bugs from the previous version. The versions are part of the long-lived branch and were the most recent on NVIDIA's official download page when this text was published. NVIDIA published version 290.10 of its Linux drivers in November, as mentioned in two posts by an NVIDIA developer in the NVIDIA Linux forums at Nvnews.net (1, 2).