Root/Documentation/fb/viafb.txt

1
2        VIA Integration Graphic Chip Console Framebuffer Driver
3
4[Platform]
5-----------------------
6    The console framebuffer driver is for graphics chips of
7    VIA UniChrome Family(CLE266, PM800 / CN400 / CN300,
8                        P4M800CE / P4M800Pro / CN700 / VN800,
9                        CX700 / VX700, K8M890, P4M890,
10                        CN896 / P4M900, VX800, VX855)
11
12[Driver features]
13------------------------
14    Device: CRT, LCD, DVI
15
16    Support viafb_mode:
17        CRT:
18            640x480(60, 75, 85, 100, 120 Hz), 720x480(60 Hz),
19            720x576(60 Hz), 800x600(60, 75, 85, 100, 120 Hz),
20            848x480(60 Hz), 856x480(60 Hz), 1024x512(60 Hz),
21            1024x768(60, 75, 85, 100 Hz), 1152x864(75 Hz),
22            1280x768(60 Hz), 1280x960(60 Hz), 1280x1024(60, 75, 85 Hz),
23            1440x1050(60 Hz), 1600x1200(60, 75 Hz), 1280x720(60 Hz),
24            1920x1080(60 Hz), 1400x1050(60 Hz), 800x480(60 Hz)
25
26    color depth: 8 bpp, 16 bpp, 32 bpp supports.
27
28    Support 2D hardware accelerator.
29
30[Using the viafb module]
31-- -- --------------------
32    Start viafb with default settings:
33        #modprobe viafb
34
35    Start viafb with with user options:
36        #modprobe viafb viafb_mode=800x600 viafb_bpp=16 viafb_refresh=60
37                  viafb_active_dev=CRT+DVI viafb_dvi_port=DVP1
38                  viafb_mode1=1024x768 viafb_bpp=16 viafb_refresh1=60
39                  viafb_SAMM_ON=1
40
41    viafb_mode:
42        640x480 (default)
43        720x480
44        800x600
45        1024x768
46        ......
47
48    viafb_bpp:
49        8, 16, 32 (default:32)
50
51    viafb_refresh:
52        60, 75, 85, 100, 120 (default:60)
53
54    viafb_lcd_dsp_method:
55        0 : expansion (default)
56        1 : centering
57
58    viafb_lcd_mode:
59        0 : LCD panel with LSB data format input (default)
60        1 : LCD panel with MSB data format input
61
62    viafb_lcd_panel_id:
63        0 : Resolution: 640x480, Channel: single, Dithering: Enable
64        1 : Resolution: 800x600, Channel: single, Dithering: Enable
65        2 : Resolution: 1024x768, Channel: single, Dithering: Enable (default)
66        3 : Resolution: 1280x768, Channel: single, Dithering: Enable
67        4 : Resolution: 1280x1024, Channel: dual, Dithering: Enable
68        5 : Resolution: 1400x1050, Channel: dual, Dithering: Enable
69        6 : Resolution: 1600x1200, Channel: dual, Dithering: Enable
70
71        8 : Resolution: 800x480, Channel: single, Dithering: Enable
72        9 : Resolution: 1024x768, Channel: dual, Dithering: Enable
73        10: Resolution: 1024x768, Channel: single, Dithering: Disable
74        11: Resolution: 1024x768, Channel: dual, Dithering: Disable
75        12: Resolution: 1280x768, Channel: single, Dithering: Disable
76        13: Resolution: 1280x1024, Channel: dual, Dithering: Disable
77        14: Resolution: 1400x1050, Channel: dual, Dithering: Disable
78        15: Resolution: 1600x1200, Channel: dual, Dithering: Disable
79        16: Resolution: 1366x768, Channel: single, Dithering: Disable
80        17: Resolution: 1024x600, Channel: single, Dithering: Enable
81        18: Resolution: 1280x768, Channel: dual, Dithering: Enable
82        19: Resolution: 1280x800, Channel: single, Dithering: Enable
83
84    viafb_accel:
85        0 : No 2D Hardware Acceleration
86        1 : 2D Hardware Acceleration (default)
87
88    viafb_SAMM_ON:
89        0 : viafb_SAMM_ON disable (default)
90        1 : viafb_SAMM_ON enable
91
92    viafb_mode1: (secondary display device)
93        640x480 (default)
94        720x480
95        800x600
96        1024x768
97        ... ...
98
99    viafb_bpp1: (secondary display device)
100        8, 16, 32 (default:32)
101
102    viafb_refresh1: (secondary display device)
103        60, 75, 85, 100, 120 (default:60)
104
105    viafb_active_dev:
106        This option is used to specify active devices.(CRT, DVI, CRT+LCD...)
107        DVI stands for DVI or HDMI, E.g., If you want to enable HDMI,
108        set viafb_active_dev=DVI. In SAMM case, the previous of
109        viafb_active_dev is primary device, and the following is
110        secondary device.
111
112        For example:
113        To enable one device, such as DVI only, we can use:
114            modprobe viafb viafb_active_dev=DVI
115        To enable two devices, such as CRT+DVI:
116            modprobe viafb viafb_active_dev=CRT+DVI;
117
118        For DuoView case, we can use:
119            modprobe viafb viafb_active_dev=CRT+DVI
120            OR
121            modprobe viafb viafb_active_dev=DVI+CRT...
122
123        For SAMM case:
124        If CRT is primary and DVI is secondary, we should use:
125            modprobe viafb viafb_active_dev=CRT+DVI viafb_SAMM_ON=1...
126        If DVI is primary and CRT is secondary, we should use:
127            modprobe viafb viafb_active_dev=DVI+CRT viafb_SAMM_ON=1...
128
129    viafb_display_hardware_layout:
130        This option is used to specify display hardware layout for CX700 chip.
131        1 : LCD only
132        2 : DVI only
133        3 : LCD+DVI (default)
134        4 : LCD1+LCD2 (internal + internal)
135        16: LCD1+ExternalLCD2 (internal + external)
136
137    viafb_second_size:
138        This option is used to set second device memory size(MB) in SAMM case.
139        The minimal size is 16.
140
141    viafb_platform_epia_dvi:
142        This option is used to enable DVI on EPIA - M
143        0 : No DVI on EPIA - M (default)
144        1 : DVI on EPIA - M
145
146    viafb_bus_width:
147        When using 24 - Bit Bus Width Digital Interface,
148        this option should be set.
149        12: 12-Bit LVDS or 12-Bit TMDS (default)
150        24: 24-Bit LVDS or 24-Bit TMDS
151
152    viafb_device_lcd_dualedge:
153        When using Dual Edge Panel, this option should be set.
154        0 : No Dual Edge Panel (default)
155        1 : Dual Edge Panel
156
157    viafb_lcd_port:
158        This option is used to specify LCD output port,
159        available values are "DVP0" "DVP1" "DFP_HIGHLOW" "DFP_HIGH" "DFP_LOW".
160        for external LCD + external DVI on CX700(External LCD is on DVP0),
161        we should use:
162            modprobe viafb viafb_lcd_port=DVP0...
163
164Notes:
165    1. CRT may not display properly for DuoView CRT & DVI display at
166       the "640x480" PAL mode with DVI overscan enabled.
167    2. SAMM stands for single adapter multi monitors. It is different from
168       multi-head since SAMM support multi monitor at driver layers, thus fbcon
169       layer doesn't even know about it; SAMM's second screen doesn't have a
170       device node file, thus a user mode application can't access it directly.
171       When SAMM is enabled, viafb_mode and viafb_mode1, viafb_bpp and
172       viafb_bpp1, viafb_refresh and viafb_refresh1 can be different.
173    3. When console is depending on viafbinfo1, dynamically change resolution
174       and bpp, need to call VIAFB specified ioctl interface VIAFB_SET_DEVICE
175       instead of calling common ioctl function FBIOPUT_VSCREENINFO since
176       viafb doesn't support multi-head well, or it will cause screen crush.
177
178
179[Configure viafb with "fbset" tool]
180-----------------------------------
181    "fbset" is an inbox utility of Linux.
182    1. Inquire current viafb information, type,
183           # fbset -i
184
185    2. Set various resolutions and viafb_refresh rates,
186           # fbset <resolution-vertical_sync>
187
188       example,
189           # fbset "1024x768-75"
190       or
191           # fbset -g 1024 768 1024 768 32
192       Check the file "/etc/fb.modes" to find display modes available.
193
194    3. Set the color depth,
195           # fbset -depth <value>
196
197       example,
198           # fbset -depth 16
199
200
201[Configure viafb via /proc]
202---------------------------
203    The following files exist in /proc/viafb
204
205    supported_output_devices
206
207        This read-only file contains a full ',' separated list containing all
208        output devices that could be available on your platform. It is likely
209        that not all of those have a connector on your hardware but it should
210        provide a good starting point to figure out which of those names match
211        a real connector.
212        Example:
213        # cat /proc/viafb/supported_output_devices
214
215    iga1/output_devices
216    iga2/output_devices
217
218        These two files are readable and writable. iga1 and iga2 are the two
219        independent units that produce the screen image. Those images can be
220        forwarded to one or more output devices. Reading those files is a way
221        to query which output devices are currently used by an iga.
222        Example:
223        # cat /proc/viafb/iga1/output_devices
224        If there are no output devices printed the output of this iga is lost.
225        This can happen for example if only one (the other) iga is used.
226        Writing to these files allows adjusting the output devices during
227        runtime. One can add new devices, remove existing ones or switch
228        between igas. Essentially you can write a ',' separated list of device
229        names (or a single one) in the same format as the output to those
230        files. You can add a '+' or '-' as a prefix allowing simple addition
231        and removal of devices. So a prefix '+' adds the devices from your list
232        to the already existing ones, '-' removes the listed devices from the
233        existing ones and if no prefix is given it replaces all existing ones
234        with the listed ones. If you remove devices they are expected to turn
235        off. If you add devices that are already part of the other iga they are
236        removed there and added to the new one.
237        Examples:
238        Add CRT as output device to iga1
239        # echo +CRT > /proc/viafb/iga1/output_devices
240
241        Remove (turn off) DVP1 and LVDS1 as output devices of iga2
242        # echo -DVP1,LVDS1 > /proc/viafb/iga2/output_devices
243
244        Replace all iga1 output devices by CRT
245        # echo CRT > /proc/viafb/iga1/output_devices
246
247
248[Bootup with viafb]:
249--------------------
250    Add the following line to your grub.conf:
251    append = "video=viafb:viafb_mode=1024x768,viafb_bpp=32,viafb_refresh=85"
252
253

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