xref: /netbsd/share/man/man4/drm.4 (revision 6f4dacc8)

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.Dd March 10, 2021
.Dt DRM 4
.Os
.Sh NAME
.Nm drm
.Nd Direct Rendering Manager (DRI kernel support)
.Sh SYNOPSIS
.Cd i915drm*       at drm?
.Cd mach64drm*     at drm?
.Cd mgadrm*        at drm?
.Cd r128drm*       at drm?
.Cd radeondrm*     at drm?
.Cd savagedrm*     at drm?
.Cd sisdrm*        at drm?
.Cd tdfxdrm*       at drm?
.Pp
.Cd options        DRM_DEBUG
.Cd options        DRM_NO_AGP
.Cd options        DRM_MAX_RESOLUTION_HORIZONTAL=integer
.Cd options        DRM_MAX_RESOLUTION_VERTICAL=integer
.Sh DESCRIPTION
The Direct Rendering Manager is part of the Direct Rendering
Infrastructure for supporting video acceleration (3d acceleration,
mostly).
.Pp
The
.Nm
drivers provide support for the following chipsets:
.Bl -tag -width XsavagedrmXXX -offset indent -compact
.It i915drm
Intel i915, i945
.It mach64drm
Mach64 (3D Rage Pro, Rage)
.It mgadrm
Matrox G[24]00, G[45]50
.It r128drm
ATI Rage 128
.It radeondrm
ATI Radeon
.It savagedrm
S3 Savage
.It sisdrm
SiS
.It tdfxdrm
3dfx (Voodoo)
.It viadrm
VIA
.El
.Pp
To make use of the driver, the kernel must include
.Xr agp 4
(for some drivers, using
.Cd options        DRM_NO_AGP
instead may be sufficient),
.Xr X 7
must be compiled with DRI support, Mesa DRI drivers must be installed,
the appropriate
.Pa /dev/dri/card*
device must exist, and DRI must be enabled in the X configuration
file.
.Xr X 7
provided with
.Nx
and compiled from
.Xr pkgsrc 7
do so automatically where supported.
.Pp
With some drivers (at least
.Xr radeon 4 ) ,
in some cases the driver does not choose the resolution correctly.
The options
.Dv DRM_MAX_RESOLUTION_HORIZONTAL
and
.Dv DRM_MAX_RESOLUTION_VERTICAL
allow limiting the maximum resolution in X and Y direction.
.Pp
.Xr X 7
will attempt to create the device node automatically.
To create the device node manually:
.Bd -literal -offset indent
mkdir -p /dev/dri
mknod /dev/dri/card0 c 180 0
chgrp wheel /dev/dri/card0
chmod 0660 /dev/dri/card0
.Ed
.Pp
To enable DRI in the X configuration add the following to either
.Pa xorg.conf
for
.Xr Xorg 1
or
.Pa XF86Config
for
.Xr XFree86 1
:
.Bd -literal -offset indent
Section "Module"
        ...
        Load  "dri"
        Load  "dri2"
        Load  "glx"
EndSection
\&...
Section "DRI"
        Group "wheel"
        Mode 0660
EndSection
.Ed
.Pp
Debugging output can be enabled and disabled by setting the
.Xr sysctl 8
node
.Ar hw.dri.debug .
Additional information can be obtained from the
.Xr sysctl 8
nodes
.Ar hw.dri ,
.Ar hw.dri.card0 ,
.Ar hw.dri.card1 ,
etc.
.Sh SEE ALSO
.Xr XFree86 1 ,
.Xr Xorg 1 ,
.Xr agp 4 ,
.Xr XF86Config 5 ,
.Xr xorg.conf 5 ,
.Xr X 7 ,
.Pa /usr/X11R[67]/lib/X11/doc/README.DRI
.Pp
.Lk http://dri.freedesktop.org/ "Direct Rendering Infrastructure"
.Sh HISTORY
DRM was first available for Linux.
Subsequently Eric Anholt ported the DRM kernel modules to
.Fx .
Erik Reid adapted the
.Fx
DRM kernel modules to
.Nx .
As DRM continued to develop the
.Nx
support was neglected.
Tonnerre Lombard got the DRM modules working again, but DRM
development once again left the
.Nx
support behind.
Finally Yorick Hardy took the
.Fx
DRM source and managed to get it compiling and working again on
.Nx ,
thanks largely to the efforts of all those mentioned above.
Subsequently Matthias Drochner improved the DRM file hierarchy for
.Nx
and committed the DRM kernel drivers.
Matthew Green cleaned up this port and merged a set of newer
drivers, with Arto Huusko and FUKAUMI Naoki helping to get
the latest Mesa port up to date.
.Pp
The
.Nm
drivers appeared in
.Nx 5.0 .
.Sh AUTHORS
.An -nosplit
.An Eric Anholt ,
.An Terry Barnaby ,
.An Erdi Chen ,
.An Michel Daenzer ,
.An Leif Delgass ,
.An Frank C. Earl ,
.An Rickard E. Faith ,
.An Jose Fonseca ,
.An Nicolai Haehnle ,
.An Jeff Hartmann ,
.An Thomas Hellstrom ,
.An Gareth Hughes ,
.An Felix Kuehling ,
.An Sung-Ching Lin ,
.An Kevin E. Martin ,
.An Daryll Strauss ,
.An Keith Whitwell
.Sh CAVEATS
In case of errors,
.Pa /dev/dri/card0
may be changed, make sure to recreate it in that case.
.Pp
.Cd options DRM_DEBUG
can slow DRI down a lot; disable it once
.Nm
works.