01 June 2009, 18:52

Kernel Log: What's coming in 2.6.30 – Drivers: New drivers for audio, video, USB hardware, netbooks and notebooks

Kernel Log Penguin

Thorsten Leemhuis

The kernel developers have added new features to thousands of the Linux kernel's existing drivers and integrated numerous additional drivers. This further increases the variety of hardware supported by Linux.

A few days ago, Linus Torvalds released the seventh Linux 2.6.30 release candidate. According to Torvalds, most of the merged changes are minor, and the next big kernel version is nearing completion – although Torvalds does still anticipate an eighth release candidate. The Kernel Log takes this opportunity to discuss what's new in the driver arena of Linux 2.6.30; the final version of the forthcoming kernel will probably be released in one to three weeks.

Audio, video

The audio drivers of Linux 2.6.30 will roughly be in line with the status of the ALSA 1.0.20 drivers. Aside from a driver for Atmel AC97 codecs and Xonar Essence STX support, this curiously also includes a new ISA driver for various sound cards of the Turtle Beach MultiSound series. The ASoC (ALSA System on Chip) framework and the HD audio drivers were also overhauled quite extensively. The latter now offer improved runtime reconfiguration via Sysfs (1, 2, 3). As in every new kernel version, the developers also considerably extended the white lists that allow hardware-specific adjustments ("quirks") to be made automatically – see the list at the end of this article for details.

Innumerable changes were once again made to the V4L/DVB subsystem – there are so many that even the maintainer of this kernel area didn't want to summarise them. One of the items included for the first time is the cx231xx driver for TV hardware with Conextant's series cx231xx chips connected via USB. New is also the hdpvr driver for the Hauppauge HD PVR, also connected via USB. With sq905, sq905c and mr97310a, the Gspca framework now offers three additional drivers for chips that are used in the webcams of various vendors. Support has also been added for Sony PlayTV and Intel CE6230 DVB-T hardware; see the list at the end of this article for numerous new and improved drivers.

Kernel Log: What's coming in 2.6.30

Further parts of the Kernel Log's "What's coming in 2.6.30" mini series which provide an overview of the most important changes of the forthcoming kernel version:

1. Network: New Wi-Fi drivers and other network novelties

2. File systems: New and revamped file systems

3. Storage: RAID improvements, optimised CFQ Scheduler, SAS drivers

The article "Steady Growth - What's new in Linux 2.6.29" describes the new features of the kernel version in the main development line current at the article's time of writing. Further background and information about developments in the Linux kernel and its environment can also be found in previous issues of the Kernel Log at The H Open Source.

Graphics

The developers have made numerous changes to improve the emerging GEM and KMS technologies so far only used in Intel GPUs. A patch of almost 650 Kbytes integrates the microcode for the Radeon R600 and R700 GPUs used in the Radeon-HD models of the 2000, 3000, and 4000 series. The newly integrated support of these GPUs in the kernel's Direct Rendering Manager (DRM) allows the DRM to provide recent graphics drivers with Xvideo functionality and 2D acceleration. Also newly supported in the DRM is the chipset for RS600 motherboards. The Intel drivers are now capable of TV output on some of the boards and can handle the G33 and G41 chipsets.

USB, FireWire and hardware monitoring

A lot of changes were made to the USB subsystem – for example, the USB storage driver was split to facilitate maintenance. The developers removed the phidget driver; as an alternative, they recommend a userspace driver which offers better support for phidgets components.

The FireWire subsystem now offers broadcast channel support and asynchronous stream transmission. Further details about these changes can be found in the FireWire developers' wiki.

The I2C subsystem supports many recent chipsets for motherboards by Nvidia (MCP67, MCP73, MCP78S and MCP79), AMD (SB800), and Broadcom (HT1100). The hardware monitoring subsystem now supports FSC's Syleus, Hades and Nuvoton chips, and the Winbond Nuvoton. The hdaps (Hard Drive Active Protection System) drivers were also improved.

Notebooks and input devices

New in Linux 2.6.30 is the dell-wmi driver, although it currently only forwards hotkey events in Dell notebooks. The sony-laptop and thinkpad-acpi drivers have undergone major restructuring – the former now supports more notebook models and event types, whilst the latter offers improved brightness control for ThinkPads. See the links at the end of this article to find out more about these changes.

The drivers for USB input devices (HIDs/Human Interface Devices) now offer autosuspend functionality, which can slightly improve the battery life of notebooks. The developers have also improved the Apple mini aluminium keyboard and multi-touch support (1, documentation).

Staging

A host of changes have been introduced in the staging area. The staging area is a special kernel section used for collecting and improving drivers which don't (yet) match the kernel developers' quality standards – for this reason, some distributions don't even include the staging drivers.

The Git-Pull request lists all the major changes – all of the Comedi framework drivers, for instance, have now been included. Another first timer is the rt3070 driver for recent RaLink WLAN chipsets, which, like its fellow RaLink drivers in the staging area, contains its own WLAN stack. This stack doesn't fully co-operate with some of the userspace programs like the NetworkManager, which is used in many distributions. It is, therefore, rather unlikely that these drivers will eventually be relocated from the staging area into the kernel's network subsystem – the developers are more likely to extend the rt2x00 driver for other RaLink chipsets to support more recent chips. However, they have planned to do this for the chips supported by the rt2860 and rt2870 drivers for quite some time without any tangible results.

Minor gems

What we have mentioned so far only describes the most important changes the kernel hackers have recently made to the relevant Linux code. Many further changes can be found in the following list containing the respective commits in the main development branch; the links directly display the changes in a web frontend, where the commit comment and the patch itself offer more information about the perhaps minor, but by no means unimportant changes.

Drivers

Relevant Git-Pull requests:

ALSA: 1, 2
Driver core: 1, 2
DRM: 1, 2
FireWire: 1
I2C/Hwmon: 1, 2
Staging: 1
USB: 1
V4L/DVB: 1, 2

Audio

Audio – Quirks

Audio – ASoC

Graphics

I2C and Hardware-Monitoring

Input

Notebooks and Netbooks

Staging

USB

Video

Various

Further background and information about developments in the Linux kernel and its environment can also be found in previous issues of the Kernel Log at The H Open Source:

Older Kernel Logs can be found in the archives or by using the search function at The H Open Source. (thl/c't)

(djwm)

« previous | next »

Print Version | Send by email | Permalink: http://h-online.com/-741837