xref: /linux/Documentation/fb/viafb.rst (revision e2ad626f8f409899baf1bf192d0533a851128b19)
1=======================================================
2VIA Integration Graphic Chip Console Framebuffer Driver
3=======================================================
4
5Platform
6--------
7    The console framebuffer driver is for graphics chips of
8    VIA UniChrome Family
9    (CLE266, PM800 / CN400 / CN300,
10    P4M800CE / P4M800Pro / CN700 / VN800,
11    CX700 / VX700, K8M890, P4M890,
12    CN896 / P4M900, VX800, VX855)
13
14Driver features
15---------------
16    Device: CRT, LCD, DVI
17
18    Support viafb_mode::
19
20	CRT:
21	    640x480(60, 75, 85, 100, 120 Hz), 720x480(60 Hz),
22	    720x576(60 Hz), 800x600(60, 75, 85, 100, 120 Hz),
23	    848x480(60 Hz), 856x480(60 Hz), 1024x512(60 Hz),
24	    1024x768(60, 75, 85, 100 Hz), 1152x864(75 Hz),
25	    1280x768(60 Hz), 1280x960(60 Hz), 1280x1024(60, 75, 85 Hz),
26	    1440x1050(60 Hz), 1600x1200(60, 75 Hz), 1280x720(60 Hz),
27	    1920x1080(60 Hz), 1400x1050(60 Hz), 800x480(60 Hz)
28
29    color depth: 8 bpp, 16 bpp, 32 bpp supports.
30
31    Support 2D hardware accelerator.
32
33Using the viafb module
34----------------------
35    Start viafb with default settings::
36
37	#modprobe viafb
38
39    Start viafb with user options::
40
41	#modprobe viafb viafb_mode=800x600 viafb_bpp=16 viafb_refresh=60
42		  viafb_active_dev=CRT+DVI viafb_dvi_port=DVP1
43		  viafb_mode1=1024x768 viafb_bpp=16 viafb_refresh1=60
44		  viafb_SAMM_ON=1
45
46    viafb_mode:
47	- 640x480 (default)
48	- 720x480
49	- 800x600
50	- 1024x768
51
52    viafb_bpp:
53	- 8, 16, 32 (default:32)
54
55    viafb_refresh:
56	- 60, 75, 85, 100, 120 (default:60)
57
58    viafb_lcd_dsp_method:
59	- 0 : expansion (default)
60	- 1 : centering
61
62    viafb_lcd_mode:
63	0 : LCD panel with LSB data format input (default)
64	1 : LCD panel with MSB data format input
65
66    viafb_lcd_panel_id:
67	- 0 : Resolution: 640x480, Channel: single, Dithering: Enable
68	- 1 : Resolution: 800x600, Channel: single, Dithering: Enable
69	- 2 : Resolution: 1024x768, Channel: single, Dithering: Enable (default)
70	- 3 : Resolution: 1280x768, Channel: single, Dithering: Enable
71	- 4 : Resolution: 1280x1024, Channel: dual, Dithering: Enable
72	- 5 : Resolution: 1400x1050, Channel: dual, Dithering: Enable
73	- 6 : Resolution: 1600x1200, Channel: dual, Dithering: Enable
74
75	- 8 : Resolution: 800x480, Channel: single, Dithering: Enable
76	- 9 : Resolution: 1024x768, Channel: dual, Dithering: Enable
77	- 10: Resolution: 1024x768, Channel: single, Dithering: Disable
78	- 11: Resolution: 1024x768, Channel: dual, Dithering: Disable
79	- 12: Resolution: 1280x768, Channel: single, Dithering: Disable
80	- 13: Resolution: 1280x1024, Channel: dual, Dithering: Disable
81	- 14: Resolution: 1400x1050, Channel: dual, Dithering: Disable
82	- 15: Resolution: 1600x1200, Channel: dual, Dithering: Disable
83	- 16: Resolution: 1366x768, Channel: single, Dithering: Disable
84	- 17: Resolution: 1024x600, Channel: single, Dithering: Enable
85	- 18: Resolution: 1280x768, Channel: dual, Dithering: Enable
86	- 19: Resolution: 1280x800, Channel: single, Dithering: Enable
87
88    viafb_accel:
89	- 0 : No 2D Hardware Acceleration
90	- 1 : 2D Hardware Acceleration (default)
91
92    viafb_SAMM_ON:
93	- 0 : viafb_SAMM_ON disable (default)
94	- 1 : viafb_SAMM_ON enable
95
96    viafb_mode1: (secondary display device)
97	- 640x480 (default)
98	- 720x480
99	- 800x600
100	- 1024x768
101
102    viafb_bpp1: (secondary display device)
103	- 8, 16, 32 (default:32)
104
105    viafb_refresh1: (secondary display device)
106	- 60, 75, 85, 100, 120 (default:60)
107
108    viafb_active_dev:
109	This option is used to specify active devices.(CRT, DVI, CRT+LCD...)
110	DVI stands for DVI or HDMI, E.g., If you want to enable HDMI,
111	set viafb_active_dev=DVI. In SAMM case, the previous of
112	viafb_active_dev is primary device, and the following is
113	secondary device.
114
115	For example:
116
117	To enable one device, such as DVI only, we can use::
118
119	    modprobe viafb viafb_active_dev=DVI
120
121	To enable two devices, such as CRT+DVI::
122
123	    modprobe viafb viafb_active_dev=CRT+DVI;
124
125	For DuoView case, we can use::
126
127	    modprobe viafb viafb_active_dev=CRT+DVI
128
129	OR::
130
131	    modprobe viafb viafb_active_dev=DVI+CRT...
132
133	For SAMM case:
134
135	If CRT is primary and DVI is secondary, we should use::
136
137	    modprobe viafb viafb_active_dev=CRT+DVI viafb_SAMM_ON=1...
138
139	If DVI is primary and CRT is secondary, we should use::
140
141	    modprobe viafb viafb_active_dev=DVI+CRT viafb_SAMM_ON=1...
142
143    viafb_display_hardware_layout:
144	This option is used to specify display hardware layout for CX700 chip.
145
146	- 1 : LCD only
147	- 2 : DVI only
148	- 3 : LCD+DVI (default)
149	- 4 : LCD1+LCD2 (internal + internal)
150	- 16: LCD1+ExternalLCD2 (internal + external)
151
152    viafb_second_size:
153	This option is used to set second device memory size(MB) in SAMM case.
154	The minimal size is 16.
155
156    viafb_platform_epia_dvi:
157	This option is used to enable DVI on EPIA - M
158
159	- 0 : No DVI on EPIA - M (default)
160	- 1 : DVI on EPIA - M
161
162    viafb_bus_width:
163	When using 24 - Bit Bus Width Digital Interface,
164	this option should be set.
165
166	- 12: 12-Bit LVDS or 12-Bit TMDS (default)
167	- 24: 24-Bit LVDS or 24-Bit TMDS
168
169    viafb_device_lcd_dualedge:
170	When using Dual Edge Panel, this option should be set.
171
172	- 0 : No Dual Edge Panel (default)
173	- 1 : Dual Edge Panel
174
175    viafb_lcd_port:
176	This option is used to specify LCD output port,
177	available values are "DVP0" "DVP1" "DFP_HIGHLOW" "DFP_HIGH" "DFP_LOW".
178
179	for external LCD + external DVI on CX700(External LCD is on DVP0),
180	we should use::
181
182	    modprobe viafb viafb_lcd_port=DVP0...
183
184Notes:
185    1. CRT may not display properly for DuoView CRT & DVI display at
186       the "640x480" PAL mode with DVI overscan enabled.
187    2. SAMM stands for single adapter multi monitors. It is different from
188       multi-head since SAMM support multi monitor at driver layers, thus fbcon
189       layer doesn't even know about it; SAMM's second screen doesn't have a
190       device node file, thus a user mode application can't access it directly.
191       When SAMM is enabled, viafb_mode and viafb_mode1, viafb_bpp and
192       viafb_bpp1, viafb_refresh and viafb_refresh1 can be different.
193    3. When console is depending on viafbinfo1, dynamically change resolution
194       and bpp, need to call VIAFB specified ioctl interface VIAFB_SET_DEVICE
195       instead of calling common ioctl function FBIOPUT_VSCREENINFO since
196       viafb doesn't support multi-head well, or it will cause screen crush.
197
198
199Configure viafb with "fbset" tool
200---------------------------------
201
202    "fbset" is an inbox utility of Linux.
203
204    1. Inquire current viafb information, type::
205
206	   # fbset -i
207
208    2. Set various resolutions and viafb_refresh rates::
209
210	   # fbset <resolution-vertical_sync>
211
212       example::
213
214	   # fbset "1024x768-75"
215
216       or::
217
218	   # fbset -g 1024 768 1024 768 32
219
220       Check the file "/etc/fb.modes" to find display modes available.
221
222    3. Set the color depth::
223
224	   # fbset -depth <value>
225
226       example::
227
228	   # fbset -depth 16
229
230
231Configure viafb via /proc
232-------------------------
233    The following files exist in /proc/viafb
234
235    supported_output_devices
236	This read-only file contains a full ',' separated list containing all
237	output devices that could be available on your platform. It is likely
238	that not all of those have a connector on your hardware but it should
239	provide a good starting point to figure out which of those names match
240	a real connector.
241
242	Example::
243
244		# cat /proc/viafb/supported_output_devices
245
246    iga1/output_devices, iga2/output_devices
247	These two files are readable and writable. iga1 and iga2 are the two
248	independent units that produce the screen image. Those images can be
249	forwarded to one or more output devices. Reading those files is a way
250	to query which output devices are currently used by an iga.
251
252	Example::
253
254		# cat /proc/viafb/iga1/output_devices
255
256	If there are no output devices printed the output of this iga is lost.
257	This can happen for example if only one (the other) iga is used.
258	Writing to these files allows adjusting the output devices during
259	runtime. One can add new devices, remove existing ones or switch
260	between igas. Essentially you can write a ',' separated list of device
261	names (or a single one) in the same format as the output to those
262	files. You can add a '+' or '-' as a prefix allowing simple addition
263	and removal of devices. So a prefix '+' adds the devices from your list
264	to the already existing ones, '-' removes the listed devices from the
265	existing ones and if no prefix is given it replaces all existing ones
266	with the listed ones. If you remove devices they are expected to turn
267	off. If you add devices that are already part of the other iga they are
268	removed there and added to the new one.
269
270	Examples:
271
272	Add CRT as output device to iga1::
273
274		# echo +CRT > /proc/viafb/iga1/output_devices
275
276	Remove (turn off) DVP1 and LVDS1 as output devices of iga2::
277
278		# echo -DVP1,LVDS1 > /proc/viafb/iga2/output_devices
279
280	Replace all iga1 output devices by CRT::
281
282		# echo CRT > /proc/viafb/iga1/output_devices
283
284
285Bootup with viafb
286-----------------
287
288Add the following line to your grub.conf::
289
290    append = "video=viafb:viafb_mode=1024x768,viafb_bpp=32,viafb_refresh=85"
291
292
293VIA Framebuffer modes
294=====================
295
296.. include:: viafb.modes
297   :literal:
298