Kernel Log: Coming in 2.6.37 (Part 1) - Graphics
by Thorsten Leemhuis
The Nouveau driver now supports power management and can address the GeForce 320M, and the code for Intel graphics cores now supports the video units on Sandy Bridge processors, which are due to be released shortly. A number of changes to the Radeon KMS driver should improve its performance.
Linus Torvalds released the third pre-release version of Linux 2.6.37 ten days ago and then despite Thanksgiving and a trip to Tokyo, he kept to his usual tempo and the fourth pre-release version was released two days ago.
The final release of 2.6.37 will probably be in late December or early January next year. The current developer version already resembles the final version pretty closely, since kernel hackers have, as ever, used the merge window which opens the development cycle, to merge all major changes into the main development tree. The current stabilisation phase is reserved primarily for bug-fixes rather than major changes, to avoid introducing further bugs.
The Kernel Log is therefore already in a position to offer a comprehensive overview of the major changes in the new kernel version. As ever, this information will be divided into a series of articles which will deal with different functional areas in turn. The 'What's coming in 2.6.37' series kicks off with a description of changes in the area of graphics hardware support. Articles on network support, storage hardware, file systems, architecture code, drivers and other areas will be published over the next few weeks.
The big three
The Nouveau driver now supports NVAF chips such as the GeForce 320M (aka MCP89), a motherboard chip-set with integrated graphics used in some recent Macbooks. The Nouveau code is now able to utilise some power management functions on GeForce graphics chips, but is still not able to activate the fan control, with the result that fans on graphics cards without autonomous fan control, always run at maximum speed, resulting in irritating noise levels.
The code for Evergreen (HD 5000 series) Radeon graphics chips now offers blit support, which allows the use of graphics memory beyond the PCI aperture size and improves 2D and 3D performance. The latter also improves writeback support, also implemented on older Radeon graphics chips.
Drivers for Intel GPUs now support the ring buffer on Sandy Bridge processors – this is used to address the processor units for decoding and encoding video. (1, 2). Sandy Bridge processors are scheduled for release early next year and are equipped with an integrated graphics processor. The Intel KMS driver is now able to activate audio output via DisplayPort and HDMI. If problems detecting the audio capabilities of DP or HDMI output devices occur, audio output can now be activated manually (1, 2, 3).
The kernel now includes a minimal driver for controlling screen brightness for GMA500 graphics on Intel's Poulsbo chip-set. There is still no open source graphics driver or universal proprietary graphics driver usable by the primary mainstream distributions for this chip-set, which is primarily intended for embedded systems, but is also used in some netbooks. An Intel employee has told Kernel Log that Intel is aware of the issue and intends to resolve it at some point, but it is unclear whether this refers to current chip-sets or whether only future chip-sets are set to be blessed with a decent Linux driver.