Mode setting is a software operation that activates a display mode (screen resolution, color depth, and refresh rate) for a computer's display controller by using

VESA BIOS Extensions VESA BIOS Extensions (VBE) is a VESA standard, currently at version 3, that defines the interface that can be used by software to access compliant video boards at high resolutions and bit depths. This is opposed to the "traditional" int 10h BIO ...

or UEFI Graphics extensions (on more modern computers). The display mode is set by the kernel. In ''user-space mode-setting'' (UMS), the display mode is set by a

user-space A modern computer operating system usually segregates virtual memory into user space and kernel space. Primarily, this separation serves to provide memory protection and hardware protection from malicious or errant software behaviour. Kernel ...

process. Kernel mode-setting is more flexible and allows displaying of an error in the case of a fatal system error in the kernel, even when using a user-space display server. User-space mode setting would require superuser privileges for direct hardware access, so kernel-based mode setting shuns such requirement for the user-space graphics server.

Implementation

Microsoft Windows

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

versions that are NT-based use kernel mode setting. The kernel error display made possible by kernel mode setting is officially called "bug check", but more commonly known as the Blue Screen of Death.

Linux

The

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ope ...

got the prerequisite for kernel-based mode setting by accepting Intel

GEM A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, a ...

in version 2.6.28, released in December 2008. This will be replaced by Tungstens Graphics TTM (Translation Table Maps) memory manager which supports the GEM API. TTM was developed for the free and open-source drivers for Radeon and S3 Graphics graphic chipsets (''see Free and open-source graphics device driver''). Support for Intel GMA graphic chipsets was accepted in version 2.6.29, released on March 23, 2009. Support for pre-R600 ATI Radeon graphics cards was accepted in version 2.6.31, released on September 9, 2009. Support for R600 and R700 was in development within Direct Rendering Manager, DRM and was merged in version 2.6.32. Support for Evergreen (R800) was merged in version 2.6.34. As Nvidia did not release all the needed documentation for its graphics chip, development proceeded under the nouveau (software), nouveau project, which uses reverse engineering to build a working open-source driver for Nvidia cards. Nouveau was accepted in version 2.6.33 of the kernel, released on December 10, 2009. Kernel-based mode setting is not only supported by the nouveau driver, it is required. Wayland compositors (e.g. Wayland (display server protocol), Weston) and kmscon depend on kernel mode setting via ioctl.

FreeBSD

FreeBSD has support for both kernel-based mode setting and GEM for later generations of Intel GPUs (IronLake, SandyBridge, and IvyBridge) starting with version 9.1.

NetBSD

NetBSD has support for kernel-based mode setting and accelerated graphics for Intel and Radeon devices. This implementation was introduced in version 7.0 by porting the Linux 3.15 DRM/KMS code.

OpenBSD

OpenBSD has kernel-based mode setting support for Intel and Radeon GPUs. Starting with version 5.4 of OpenBSD, support for Intel GPUs is available. With the release of version 5.5, the implementation has been extended to add support for Radeon chipsets as well.

Alternatives

The following alternatives have been presented during the Linux Plumbers Conference 2013: * It was suggested to split GEM and KMS. * Atomic Display Framework, by Google's Android-Team. * Common Display Framework.

References

{{Reflist, refs= {{ cite web , url = http://kernelnewbies.org/Linux_2_6_28#head-b957b19f6139b6bbbfabaf790bf643b1746985d6 , title = Linux 2 6 28 , publisher = Linux Kernel Newbies , date = , accessdate = 2013-02-14 {{ cite web , url = https://www.phoronix.com/scan.php?page=news_item&px=NjY3Ng , title = A GEM-ified TTM Manager For Radeon , first = Michael , last = Larabel , publisher = Phoronix , date = 2008-08-26 , accessdate = 2013-02-14 {{ cite web , url = https://www.phoronix.com/scan.php?page=news_item&px=NzMxOA , title = TTM Memory Manager Gets Ready For Release , first = Michael , last = Larabel , publisher = Phoronix , date = 2009-06-10 , accessdate = 2013-02-14 {{ cite web , url = http://kernelnewbies.org/Linux_2_6_29#head-e1bab8dc862e3b477cc38d87e8ddc779a66509d1 , title = Linux 2 6 29 , publisher = Linux Kernel Newbies , date = , accessdate = 2013-02-14 {{ cite web , url = http://kernelnewbies.org/Linux_2_6_31#head-78158343fc06e5e289f2ccaf51d6a30090a46524 , title = Linux 2 6 31 , publisher = Linux Kernel Newbies , date = 2009-09-09 , accessdate = 2013-02-14 {{ cite web , url = https://www.phoronix.com/scan.php?page=article&item=amd_r600_r700_2d , title = AMD R600/700 2D Performance: Open vs. Closed Drivers , first = Michael , last = Larabel , publisher = Phoronix , date = 2009-09-30 , accessdate = 2013-02-14 {{ cite web , title = FreeBSD 9.1-RELEASE Release Notes , url= http://www.freebsd.org/releases/9.1R/relnotes.html , date = 30 December 2012 , publisher = FreeBSD Foundation {{ cite web , title = Announcing NetBSD 7.0 , url = https://netbsd.org/releases/formal-7/NetBSD-7.0.html , date = 25 September 2015 , publisher = The NetBSD Project , accessdate = 25 April 2016 {{ cite web , url=http://nouveau.freedesktop.org/wiki/KernelModeSetting/ , title=nouveau/ KernelModeSetting , publisher=freedesktop.org , date=24 August 2013 , accessdate=2014-08-11