1OPENCHROME(4) Kernel Interfaces Manual OPENCHROME(4)
2
6 openchrome - video driver for VIA Unichromes
7
9 Section "Device"
10 Identifier "devname"
11 Driver "openchrome"
12 ...
13 EndSection
14
17 openchrome is an Xorg driver for VIA chipsets that have an integrated
18 Unichrome graphics engine.
19 The openchrome driver supports the following chipsets: CLE266,
21 KM400/KN400/KM400A/P4M800, CN400/PM800/PN800/PM880, K8M800,
22 CN700/VM800/P4M800Pro, CX700, P4M890, K8M890, P4M900/VN896/CN896,
23 VX800, VX855 and VX900. The driver includes 2D acceleration and Xv
24 video overlay extensions. Flat panel, TV, and VGA outputs are sup‐
25 ported, depending on the hardware configuration.
26 3D direct rendering is available using experimental drivers from Mesa
28 (www.mesa3d.org). There is also an XvMC client library for hardware
29 acceleration of MPEG1/MPEG2 decoding (not available on the KM/N400)
30 that uses the Direct Rendering Infrastructure (DRI). The XvMC client
31 library implements a non-standard "VLD" extension to the XvMC standard.
32 The current Direct Rendering Manager (DRM) kernel module is available
33 at dri.sourceforge.net.
34 The driver supports free modes for Unichrome Pros (K8M800/K8N800,
36 PM800/PN800, and CN400). For plain Unichromes (CLE266, KM400/KN400),
37 it currently supports only a limited number of dotclocks, so if you are
38 using X modelines you must make sure that the dotclock is one of those
39 supported. Supported dotclocks on plain Unichromes are currently (in
40 MHz): 25.2, 25.312, 26.591, 31.5, 31.704, 32.663, 33.750, 35.5, 36.0,
41 39.822, 40.0, 41.164, 46.981, 49.5, 50.0, 56.3, 57.284, 64.995, 65.0,
42 65.028, 74.480, 75.0, 78.8, 81.613, 94.5, 108.0, 108.28, 122.0,
43 122.726, 135.0, 148.5, 155.8, 157.5, 161.793, 162.0, 175.5, 189.0,
44 202.5, 204.8, 218.3, 229.5. On top of this, bandwidth restrictions ap‐
45 ply for both Unichromes and Unichrome Pros.
46
48 Please refer to xorg.conf(5) for general configuration details. This
49 section only covers configuration details specific to this driver.
50 The following driver options are supported:
52 Option "AccelMethod" "string"
54 The driver supports "XAA" and "EXA" acceleration methods. The
55 default method is XAA, since EXA is still experimental. Con‐
56 trary to XAA, EXA implements acceleration for screen uploads and
57 downloads (if DRI is enabled) and for the Render/Composite ex‐
58 tension.
59 Option "AGPMem" "integer"
61 Sets the amount of AGP memory that is allocated at X server
62 startup. The allocated memory will be "integer" kB. This AGP
63 memory is used for the AGP command buffer (if the option "En‐
64 ableAGPDMA" is set to "true"), for DRI textures, and for the EXA
65 scratch area. The driver will allocate at least one system page
66 of AGP memory, or -- if the AGP command buffer is used -- at
67 least 2 MB plus one system page. If there is no room for the
68 EXA scratch area in AGP space, it will be allocated from VRAM.
69 If there is no room for DRI textures, they will be allocated
70 from the DRI part of VRAM (see the option "MaxDRIMem"). The de‐
71 fault amount of AGP is 32768 kB. Note that the AGP aperture set
72 in the BIOS must be able to accommodate the amount of AGP memory
73 specified here. Otherwise no AGP memory will be available. It
74 is safe to set a very large AGP aperture in the BIOS.
75 Option "DisableIRQ" "boolean"
77 Disables the vertical blank IRQ. This is a workaround for some
78 mainboards that have problems with IRQs coming from the
79 Unichrome engine. With IRQs disabled, DRI clients have no way
80 to synchronize their drawing to Vblank. (IRQ is disabled by de‐
81 fault on the KM400 and K8M800 chipsets.)
82 Option "DisableVQ" "boolean"
84 Disables the use of the virtual command queue. The queue is en‐
85 abled by default.
86 Option "EnableAGPDMA" "boolean"
88 Enables the AGP DMA functionality in DRM. This requires that
89 DRI is enabled and will force 2D and 3D acceleration to use AGP
90 DMA. The XvMC DRI client will also make use of this on the
91 CLE266 to consume much less CPU. (This option is enabled by de‐
92 fault, except on the K8M890 and P4M900.)
93 Option "ExaNoComposite" "boolean"
95 If EXA is enabled (using the option "AccelMethod"), this option
96 enables acceleration of compositing. Since EXA, and in particu‐
97 lar its composite acceleration, is still experimental, this is a
98 way to disable a misbehaving composite acceleration.
99 Option "ExaScratchSize" "integer"
101 Sets the size of the EXA scratch area to "integer" kB. This
102 area is used by EXA as a last place to look for available space
103 for pixmaps. Too little space will slow compositing down. This
104 option should be set to the size of the largest pixmap used. If
105 you have a screen width of over 1024 pixels and use 24 bpp, set
106 this to 8192. Otherwise you can leave this at the default 4096.
107 The space will be allocated from AGP memory if available, other‐
108 wise from VRAM.
109 Option "MaxDRIMem" "integer"
111 Sets the maximum amount of VRAM memory allocated for DRI clients
112 to "integer" kB. Normally DRI clients get half the available
113 VRAM size, but in some cases it may make sense to limit this
114 amount. For example, if you are using a composite manager and
115 you want to give as much memory as possible to the EXA pixmap
116 storage area.
117 Option "MigrationHeuristic" "string"
119 Sets the heuristic for EXA pixmap migration. This is an EXA
120 core option, and starting from Xorg server version 1.3.0 this
121 defaults to "always". The openchrome driver performs best with
122 "greedy", so you should really add this option to your configu‐
123 ration file. The third possibility is "smart".
124 Option "NoAccel" "boolean"
126 Disables the use of hardware acceleration. Acceleration is en‐
127 abled by default.
128 Option "NoXVDMA" "boolean"
130 If DRI is enabled, Xv normally uses PCI DMA to transfer video
131 images from system to frame-buffer memory. This is somewhat
132 slower than direct copies due to the limitations of the PCI bus,
133 but on the other hand it decreases CPU usage significantly, par‐
134 ticularly on computers with fast processors. Some video players
135 are buggy and will display rendering artifacts when PCI DMA is
136 used. If you experience this, or don't want your PCI bus to be
137 stressed with Xv images, set this option to "true". This option
138 has no effect when DRI is not enabled.
139 Option "RotationType" "string"
141 Enabled rotation by using RandR. The driver only support unac‐
142 celerated RandR rotations "SWRandR". Hardware rotations
143 "HWRandR" is currently unimplemented.
144 Option "Rotate" "string"
146 Rotates the display either clockwise ("CW"), counterclockwise
147 ("CCW") and upside-down ("UD"). Rotation is only supported unac‐
148 celerated. Adding option "Rotate", enables RandR rotation fea‐
149 ture. The RandR allows clients to dynamically change X screens.
150 Option "ShadowFB" "boolean"
152 Enables the use of a shadow frame buffer. This is required when
153 rotating the display, but otherwise defaults to disabled.
154 Option "SWCursor" "boolean"
156 Enables the use of a software cursor. The default is disabled:
157 the hardware cursor is used.
158 Option "TVDeflicker" "integer"
160 Specifies the deflicker setting for TV output. Valid values are
161 "0", "1", and "2". Here 0 means no deflicker, 1 means 1:1:1 de‐
162 flicker, and 2 means 1:2:1 deflicker.
163 Option "TVDotCrawl" "boolean"
165 Enables dot-crawl suppression. The default is disabled.
166 Option "TVOutput" "string"
168 Specifies which TV output to use. The driver supports "S-
169 Video", "Composite", "SC", "RGB", and "YCbCr" outputs. Note
170 that on some EPIA boards the composite-video port is shared with
171 audio-out and is selected via a jumper.
172 Option "TVPort" "string"
174 Specifies TV port. The driver currently supports "DVP0",
175 "DVP1", "DFPHigh" and "DFPLow" ports.
176 Option "TVType" "string"
178 Specifies TV output format. The driver currently supports
179 "NTSC" and "PAL" timings only.
180
182 Unichromes tend to be paired with several different TV encoders.
183 VIA Technologies VT1621
185 Still untested, as no combination with a Unichrome is known or
186 available. Supports the following normal modes: "640x480" and
187 "800x600". Use "640x480Over" and "800x600Over" for vertical
188 overscan. These modes are made available by the driver; mode‐
189 lines provided in xorg.conf will be ignored.
190 VIA Technologies VT1622, VT1622A, VT1623
192 Supports the following modes: "640x480", "800x600", "1024x768",
193 "848x480", "720x480" (NTSC only) and "720x576" (PAL only). Use
194 "640x480Over", "800x600Over", "1024x768Over", "848x480Over",
195 "720x480Over" (NTSC) and "720x576Over" (PAL) for vertical over‐
196 scan. The modes "720x480Noscale" (NTSC) and "720x576Noscale"
197 (PAL) (available on VT1622 only) provide cleaner TV output (un‐
198 scaled with only minimal overscan). These modes are made avail‐
199 able by the driver; modelines provided in xorg.conf will be ig‐
200 nored.
201
204 Xorg(1), xorg.conf(5), Xserver(1), X(7), EXA(5), Xv(5)
205
207 Authors include: ...
208X Version 11 xf86-video-openchrome 0.6.400 OPENCHROME(4)