1VIA(4) Kernel Interfaces Manual VIA(4)
2
6 via - VIA unichrome graphics driver
7
9 Section "Device"
10 Identifier "devname"
11 Driver "via"
12 ...
13 EndSection
14
16 via is an Xorg driver for VIA chipsets with onboard unichrome graphics.
17 The via driver supports the VIA CLE266, KM400/KN400, K8M/N800, PM/N800
19 and CN400 chipsets, including 2D acceleration and the Xv video overlay
20 extensions. Flat panel, TV and VGA outputs are supported, depending on
21 the hardware configuration.
22 Direct rendering 3D is available using experimental drivers in Mesa,
24 www.mesa3d.org. Also there is an XvMC client library for hardware
25 MPEG1 / MPEG2 decoding acceleration available on the CLE266, CN400,
26 PM/N800 and K8M/N800 chipsets that uses the Direct Rendering Infra‐
27 structure, DRI. The XvMC client library implements a nonstandard "VLD"
28 extension to the XvMC standard. The current Direct Rendering Manager
29 Linux kernel module is available at dri.sourceforge.net.
30 The driver supports free modes for Unichome Pro chipsets. (K8M/N800,
32 PM/N800 and CN400). Currently for Unichrome chipsets, it only supports
33 a limited number of dotclocks, so if you are using X modelines, you
34 must make sure that the dotclock is one of those supported. Supported
35 dotclocks on Unichromes are currently (MHz): 25.2, 25.312, 26.591,
36 31.5, 31.704, 32.663, 33.750, 35.5, 36.0, 39.822, 40.0, 41.164, 46.981,
37 49.5, 50.0, 56.3, 57.284, 64.995, 65.0, 65.028, 74.480, 75.0, 78.8,
38 81.613, 94.5, 108.0, 108.28, 122.0, 122.726, 135.0, 148.5, 155.8,
39 157.5, 161.793, 162.0, 175.5, 189.0, 202.5, 204.8, 218.3, 229.5. On top
40 of this, bandwidth restrictions apply both for Unichromes and Unichrome
41 Pros.
42
44 Please refer to xorg.conf(5) for general configuration details. This
45 section only covers configuration details specific to this driver.
46 The following driver options are supported
48 Option "NoAccel" "boolean"
50 Disable or enable acceleration. Default: acceleration is
51 enabled.
52 Option "HWCursor" "boolean"
54 Disable or enable use of hardware cursors. The default is
55 enabled.
56 Option "SWCursor" "boolean"
58 Disable or enable the use of a software cursor. The default is
59 disabled.
60 Option "ShadowFB" "boolean"
62 Use a shadow frame buffer. This is required when rotating the
63 display, but otherwise defaults to disabled.
64 Option "VideoRAM" "boolean"
66 Override the VideoRAM auto detection. This should never be
67 needed.
68 Option "Rotate" "string"
70 Rotate the display either clockwise ("CW") or counter clockwise
71 ("CCW"). Rotation is only supported unaccelerated.
72 Option "ActiveDevice" "string"
74 Specify the active device combination. Any string containing
75 "CRT", "LCD", "TV" should be possible. The default is to use
76 what is detected. The driver is currently unable to use LCD and
77 TV simultaneously, and will favour the LCD.
78 Option "LCDDualEdge" "boolean"
80 Use dual edge mode to set the LCD.
81 Option "Center" "boolean"
83 Disable or enable image centering on DVI displays.
84 Option "PanelSize" "string"
86 Specify the size (width x height) of the LCD panel attached to
87 the system. Sizes 640x480, 800x600, 1024x768, 1280x1024, and
88 1400x1050 are supported.
89 Option "TVDotCrawl" "boolean"
91 Disable or enable dotcrawl.
92 Option "TVDeflicker" "integer"
94 Specify deflicker setting for TV output. Valid values are 0,1,2
95 0) No deflicker, 1) 1:1:1 deflicker, 2) 1:2:1 deflicker.
96 Option "TVType" "string"
98 Specify TV output format. The driver currently supports "NTSC"
99 and "PAL" timings only.
100 Option "TVOutput" "string"
102 Specify which TV output to use. The driver supports "S-Video",
103 "Composite", "SC", "RGB" and "YCbCr" outputs. Note that on some
104 EPIA boards the composite video port is shared with audio out
105 and jumper selected.
106 Option "DisableVQ" "boolean"
108 Disable or enable the use of VQ. VQ is enabled by default.
109 Option "DRIXINERAMA" "boolean"
111 Set DRI Xinerama mode. Currently unsupported.
112 Option "DisableIRQ" "boolean"
114 Disables Vblank IRQ. A workaround for some mainboards that have
115 problems with IRQs from the unichrome chip. With IRQ disabled,
116 DRI clients have no way to sync drawing to Vblank.
117 Option "EnableAGPDMA" "boolean"
119 Enable the AGP DMA functionality in DRM. This requires that DRI
120 is enabled and will force 2D, and 3D acceleration to use AGP
121 DMA. The XvMC DRI client will also make use of this on the
122 CLE266 to consume much less CPU.
123 Option "NoAGPFor2D" "boolean"
125 With this option on, 2D acceleration will not use AGP DMA even
126 if it is enabled.
127 Option "NoXVDMA" "boolean"
129 If DRI is enabled, Xv normally uses PCI DMA to transfer video
130 images from system to frame-buffer memory. This is somewhat
131 slower than direct copies due to the limitations of the PCI bus,
132 but on the other hand it decreases CPU usage significantly. Par‐
133 ticularly on computers with fast processors. Some video players
134 are buggy and will display rendering artifacts when PCI DMA is
135 used. If you experience this, or don't want your PCI bus to be
136 stressed with Xv images, set this option to "true". This option
137 has no effect if DRI is not enabled.
138 Option "AccelMethod" "string"
140 The driver supports "XAA" and "EXA" acceleration methods. The
141 default method is XAA, since EXA is still experimental. Contrary
142 to XAA. EXA implements acceleration for screen uploads and down‐
143 lads (if DRI is enabled) and the Render / Composite extension.
144 Option "EXANoComposite" "boolean"
146 If Exa is enabled using the above option, Don't accelerate com‐
147 posite. Since EXA, and in particular, it's composite accelera‐
148 tion is still experimental, This is a way to disable exa compos‐
149 ite acceleration.
150
153 Unichromes tend to be paired with several different TV Encoders.
154 VIA Technologies VT1621
156 Untested as no combination with Unichrome is known or available.
157 Supports the following normal modes: "640x480" and "800x600".
158 Use "640x480Over" and "800x600Over" for vertical overscan. These
159 modes are made available by the driver and modelines provided in
160 xorg.conf will be ignored.
161 VIA Technologies VT1622, VT1622A, VT1623
163 Supports the following modes: "640x480", "800x600", "1024x768",
164 "848x480", "720x480" (NTSC only) and "720x576" (PAL only). Use
165 "640x480Over", "800x600Over", "1024x768Over", "848x480Over",
166 "720x480Over" (NTSC) and "720x576Over" (PAL) for vertical over‐
167 scan. The modes "720x480Noscale" (NTSC) and "720x576Noscale"
168 (PAL) (VT1622 only) provide cleaner TV output (unscaled with
169 only minimal overscan). These modes are made available by the
170 driver and modelines provided in xorg.conf will be ignored.
171
174 Xorg(1), xorg.conf(5), xorgconfig(1), Xserver(1), X(7)
175
177 Authors include: ...
178X Version 11 xf86-video-via 0.2.2 VIA(4)