Kapittel 13. Arbeidsstasjon

Nå når tjenerutrullingen er over, så kan administratorene fokusere på installasjon av individuelle arbeidsstasjoner, og lage et typisk oppsett.

13.1. Oppsett av X11-tjeneren

Å sette opp det grafiske grensesnittet for første gang kan til tider være vanskelig; aller siste skjermkort fungerer ofte ikke perfekt med X.org-versjonen som leveres i Debians stabile versjon.

A brief reminder: X.org is the software component that allows graphical applications to display windows on screen. It includes a driver that makes efficient use of the video card. The features offered to the graphical applications are exported through a standard interface, X11 (Stretch contains version X11R7.7).

PERSPEKTIV X11, XFree86 og X.org

X11 is the graphical system most widely used on Unix-like systems (also available for Windows and Mac OS). Strictly speaking, the term “X11” only refers to a protocol specification, but it is also used to refer to the implementation in practice.

X11 had a rough start, but the 1990s saw XFree86 emerge as the reference implementation because it was free software, portable, and maintained by a collaborative community. However, the rate of evolution slowed down near the end when the software only gained new drivers. That situation, along with a very controversial license change, led to the X.org fork in 2004. This is now the reference implementation, and Debian Stretch uses X.org version 7.7.

Current versions of X.org are able to autodetect the available hardware: this applies to the video card and the monitor, as well as keyboards and mice; in fact, it is so convenient that the package no longer even creates a /etc/X11/xorg.conf configuration file.

Tastaturoppsettet er for tiden definert i /etc/default/keyboard. Denne filen brukes både til å sette opp tekstkonsollen og det grafiske grensesnittet, og det håndteres av keyboard-configuration-pakken. Detaljer om å sette opp tastaturet er tilgjengelig i Seksjon 8.1.2, «Oppsett av tastaturet».

Pakken xserver-xorg-core-pakken gir en generisk X-tjener, som brukes av 7.x versjoner av X.org. Denne serveren er modulbasert, og bruker et sett av uavhengige drivere for å håndtere de mange forskjellige typene av skjermkort. Å installere xserver-xorg sørger for at både tjeneren og minst én skjermdriver er installert.

Note that if the detected video card is not handled by any of the available drivers, X.org tries using the VESA and fbdev drivers. VESA is a generic driver that should work everywhere, but with limited capabilities (fewer available resolutions, no hardware acceleration for games and visual effects for the desktop, and so on) while fbdev works on top of the kernel's framebuffer device. Nowadays the X server runs without any administrative privileges (this used to be required to be able to configure the screen) and thus its log file is now stored in the user's home directory in ~/.local/share/xorg/Xorg.0.log (whereas it used to be in /var/log/Xorg.0.log for versions older than Stretch). That log file is where one would look to know what driver is currently in use. For example, the following snippet matches what the intel driver outputs when it is loaded:

(==) Matched intel as autoconfigured driver 0
(==) Matched modesetting as autoconfigured driver 1
(==) Matched vesa as autoconfigured driver 2
(==) Matched fbdev as autoconfigured driver 3
(==) Assigned the driver to the xf86ConfigLayout
(II) LoadModule: "intel"
(II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so

EKSTRA Proprietære drivere

Noen skjermkortfabrikanter (spesielt nVidia) nekter å publisere hardvarespesifikasjonene som ville være nødvendig for å implementere gode gratis drivere. De leverer, imidlertid, proprietære drivere som gjør det mulig å bruke maskinvaren deres. Denne politikken er lite oppløftende, fordi selv når den medfølgende driveren finnes, er den vanligvis ikke så polert som den skal være. Enda viktigere, den følger ikke nødvendigvis X.Org-oppdateringene, som kan hindre den nyeste tilgjengelige driveren fra å laste riktig (eller i det hele tatt). Vi kan ikke godta denne oppførselen, og vi anbefaler at du unngår disse produsentene, og heller favoriserer mer samarbeidende produsenter.

If you still end up with such a card, you will find the required packages in the non-free section: nvidia-driver for nVidia cards. It requires a matching kernel module. Building the module can be automated by installing the package nvidia-kernel-dkms (for nVidia).

The “nouveau” project aims to develop a free software driver for nVidia cards and is the default driver that you get for nVidia cards in Debian. As of Stretch, its feature set and performance do not match the proprietary driver. In the developers' defense, we should mention that the required information can only be gathered by reverse engineering, which makes things difficult. The free driver for ATI video cards, called “radeon”, is much better in that regard although it often requires non-free firmware.