General FAQ
===========
:toc:
Cyril Brulebois <kibi@debian.org>


Input drivers
-------------

 * _How do I configure input for X?_ +
   Look at the link:../howto/configure-input.html[how to configure input] documentation.

 * _Why can’t I kill X through `Ctrl+Alt+Backspace`?_ +
   That’s explained in the above-mentioned documentation.


<<<
Video drivers
-------------

All drivers
~~~~~~~~~~~

 * _What’s wrong with the DPI setting?_ +
   By the default, the X server uses 96 DPI, as seen on upstream bug
   https://bugs.freedesktop.org/show_bug.cgi?id=23705[#23705] (in
   particular
   https://bugs.freedesktop.org/show_bug.cgi?id=23705#c6[Keith’s comment]). A
   particular DPI setting can be set through desktop environment’s
   preferences, through the `-dpi` X server command line option (see
   ++Xserver++’s manual page), or through ++xrandr++’s `--dpi` option.

 * _How do I get some info about 3D support?_ +
   Look at the link:../howto/build-mesa.html[instructions to build mesa],
   there are a few commands to learn about 3D support, the current driver,
   etc.

Ati driver
~~~~~~~~~~

 * _Why is it I’m getting low performances, or even crashes?_ +
   Make sure you have installed the
   link:https://packages.debian.org/firmware-linux&exact=1[`firmware-linux`
   package].  The driver might still be working without the firmware,
   but using code paths which aren’t supported as well as the “normal”
   ones.

Intel driver
~~~~~~~~~~~~

 * _Why isn’t it working?_ +
   KMS is mandatory, as documented in its `README.Debian` (view it
   online:
   https://salsa.debian.org/xorg-team/driver/xserver-xorg-video-intel/blob/debian-unstable/debian/README.Debian?viewer=simple[salsa.debian.org]). You
   probably disabled KMS or didn’t include it in your kernel
   configuration if you’re using a custom kernel.

 * _X is crashing all the time with my “old” Intel card. What can I do?_ +
   Unfortunately, old cards are not very well supported, and you can’t
   do much more than switching to a generic driver, like `fbdev` or
   `vesa`, as documented in `README.Debian` (view it online:
   https://salsa.debian.org/xorg-team/driver/xserver-xorg-video-intel/blob/debian-unstable/debian/README.Debian?viewer=simple[salsa.debian.org]). Please
   note that you need to disable `KMS` if you want to use the `vesa`
   driver. A minimal `xorg.conf` would look like:
----
Section "Device"
    Identifier "MyBuggyCard"
    Driver     "fbdev"
EndSection
----

Nouveau driver
~~~~~~~~~~~~~~

 * _Why isn’t it working?_ +
   Since it’s still considered experimental by its authors, the
   interfaces aren’t stable yet, so the driver has particular
   dependencies on the kernel, which are documented in `README.Debian`
   (view it online:
   https://salsa.debian.org/xorg-team/driver/xserver-xorg-video-nouveau/blob/debian-unstable/debian/README.Debian?viewer=simple[salsa.debian.org]).


<<<
Others
------

Session management
~~~~~~~~~~~~~~~~~~

 * _How to start a bare X session (without Gnome, KDE, etc.)?_ +
   Assuming there’s no X running on the `:1` display, run this from a
   VT:
----
startx /usr/bin/xterm -- :1
----
