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 Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system. The first version of Window ...

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 Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...

drivers for

Radeon Radeon () is a brand of computer products, including graphics processing units, random-access memory, RAM disk software, and solid-state drives, produced by Radeon Technologies Group, a division of AMD. The brand was launched in 2000 by ATI Tech ...

and

S3 Graphics S3 Graphics, Ltd (commonly referred to as S3) was an American computer graphics company. The company sold the Trio, ViRGE, Savage 3D, and Chrome series of graphics processors. Struggling against competition from 3dfx Interactive, ATI and Nvidi ...

graphic chipsets (''see

Free and open-source graphics device driver A free and open-source graphics device driver is a software stack which controls computer-graphics hardware and supports graphics-rendering application programming interfaces (APIs) and is released under a free and open-source software license ...

''). Support for

Intel GMA The Intel Graphics Media Accelerator (GMA) is a series of integrated graphics processors introduced in 2004 by Intel, replacing the earlier Intel Extreme Graphics series and being succeeded by the Intel HD and Iris Graphics series. This series t ...

graphic chipsets was accepted in version 2.6.29, released on March 23, 2009. Support for pre-R600

ATI Radeon Radeon () is a brand of computer products, including graphics processing units, random-access memory, RAM disk software, and solid-state drives, produced by Radeon Technologies Group, a division of AMD. The brand was launched in 2000 by ATI Tech ...

graphics cards was accepted in version 2.6.31, released on September 9, 2009. Support for R600 and R700 was in development within

DRM DRM may refer to: Government, military and politics * Defense reform movement, U.S. campaign inspired by Col. John Boyd * Democratic Republic of Madagascar, a former socialist state (1975–1992) on Madagascar * Direction du renseignement militai ...

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 A ''nouveau'' ( ), or ''vin (de) primeur'', is a wine which may be sold in the same year in which it was harvested. The most widely exported ''nouveau'' wine is French wine Beaujolais ''nouveau'' which is released on the third Thursday of N ...

project, which uses

reverse engineering Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accompli ...

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 compositor Wayland is a communication protocol that specifies the communication between a display server and its clients, as well as a C library implementation of that protocol. A display server using the Wayland protocol is called a ''Wayland compositor' ...

s (e.g.

Weston Weston may refer to: Places Australia * Weston, Australian Capital Territory, a suburb of Canberra * Weston, New South Wales * Weston Creek, a residential district of Canberra * Weston Park, Canberra, a park Canada * Weston, Nova Scotia * W ...

) and

kmscon Kmscon is a virtual console that runs in userspace and intends to replace the Linux console, a terminal built into the Linux kernel. Kmscon uses the KMS driver for its output, it is Multiseat configuration, multiseat-capable, and supports intern ...

depend on kernel mode setting via

ioctl In computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular system calls. It takes a parameter specifying a request code; th ...

FreeBSD

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

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 NetBSD is a free and open-source Unix operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is a ...

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 OpenBSD is a security-focused, free and open-source, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD 1.0. According to the website, the OpenBSD project em ...

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 The FreeBSD Foundation is a United States-based 501(c)(3) registered non-profit organization dedicated to supporting the FreeBSD project, its development and its community. Funding comes from individual and corporate donations, and is used to sp ...

{{ 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