xref: /dragonfly/share/man/man4/drm.4 (revision 31524921)
1.\"	$NetBSD: drm.4,v 1.7 2009/05/12 08:16:46 wiz Exp $
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3.\" Copyright (c) 2007 Thomas Klausner
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26.Dd November 2, 2015
27.Dt DRM 4
28.Os
29.Sh NAME
30.Nm drm
31.Nd Direct Rendering Manager (DRI kernel support)
32.Sh DESCRIPTION
33The
34.Tn Direct Rendering Manager
35is part of the
36.Tn Direct Rendering Infrastructure
37(see
38.Pa http://dri.freedesktop.org/ )
39for supporting video acceleration.
40.Pp
41The
42.Nm
43drivers provide support for the following chipsets:
44.Bl -column -offset indent ".Sy ModuleXXX" ".Sy Kernel option" ".Sy Chipset"
45.It Sy Module Ta Sy "Kernel option" Ta Sy Chipset
46.It Pa i915kms.ko Ta n/a Ta Intel i915, i945, i965, G3x, G4x
47.It Pa radeonkms.ko Ta n/a Ta AMD Radeon
48.El
49.Pp
50In most cases
51.Xr Xorg 1
52will take care of loading the appropriate modules and it is not necessary to
53modify
54.Xr loader.conf 5
55or the kernel configuration to enable
56.Nm
57support.
58.Pp
59Newer versions of
60.Xr Xorg 1 ,
61like the one from
62.Xr dports 7 ,
63do a pretty good job of figuring out the right configuration on their own,
64so having no
65.Xr xorg.conf 5
66file at all is usually the best advice.
67If for some reason an
68.Xr xorg.conf 5
69is preferred, DRI must be enabled:
70.Bd -literal
71Section "DRI"
72        Group "wheel"
73        Mode 0660
74EndSection
75.Ed
76.Pp
77With KMS, DRI is always enabled since the
78.Nm
79is always required.
80.\".Pp
81.\"In order to use two graphics cards (an on-board and another
82.\"AGP/PCI/PCIe card) with DRI, a
83.\".Pa /dev/dri/card1
84.\"link to
85.\".Pa /dev/dri/card0
86.\"has to be created using
87.\".Xr devfsctl 8 .
88.Pp
89If
90.Xr Xorg 1
91acceleration fails to initialize with a
92.Dq contigmalloc_map: failed size...
93error in dmesg, the reserve of memory for DMA ran out early and should
94be increased to a sufficiently high value by setting the
95.Va vm.dma_reserved
96loader tunable.
97A read only
98.Xr sysctl 8
99variable of the same name is provided for obtaining its current value.
100.Sh SYSCTL VARIABLES
101A number of
102.Xr sysctl 8
103variables are available:
104.Bl -tag -width ".Va hw.dri.vblank_offdelay"
105.It Va hw.dri.debug
106If set, enables debugging output.
107.It Va hw.dri.vblank_offdelay
108Specifies the delay (in milliseconds) until the vblank
109interrupt is disabled again when it's no longer needed.
110(0 = never disable, negative value = disable immediately)
111.It Va hw.dri.%d.busid
112Indicates the location of the device on the PCI bus.
113The format is:
114.Pp
115.Dl [0000-ffff]:[00-ff]:[00-1f].[0-7]
116.It Va hw.dri.%d.modesetting
117Indicates if kernel mode setting
118.Dv ( DRIVER_MODESET
119feature) is set in the device driver.
120.El
121.Sh SEE ALSO
122.Xr Xorg 1 ,
123.Xr i915kms 4 ,
124.Xr radeonkms 4 ,
125.Xr xorg.conf 5
126.Sh HISTORY
127DRM was first available for Linux.
128Subsequently Eric Anholt ported the DRM kernel modules to
129.Fx .
130.Sh CAVEATS
131Disable AIGLX if necessary
132.Pq Pa xorg.conf :
133.Bd -literal -offset indent
134Section "ServerFlags"
135        Option  "AIGLX" "off"
136EndSection
137.\"
138.\"Section "Extensions"
139.\"        Option "Composite" "Disable"
140.\"EndSection
141.Ed
142.Pp
143.Cd options DRM_DEBUG
144can slow DRI down a lot, disable it once
145.Nm
146works.
147