/Documentation/fb/intel810.txt

  1Intel 810/815 Framebuffer driver
  2 	Tony Daplas <adaplas@pol.net>
  3	http://i810fb.sourceforge.net
  4
  5	March 17, 2002
  6
  7	First Released: July 2001
  8================================================================
  9
 10A. Introduction
 11	This is a framebuffer driver for various Intel 810/815 compatible
 12graphics devices.  These would include:
 13
 14	Intel 810
 15	Intel 810E
 16	Intel 810-DC100
 17	Intel 815 Internal graphics only, 100Mhz FSB
 18	Intel 815 Internal graphics only
 19	Intel 815 Internal graphics and AGP
 20
 21B.  Features
 22
 23        - Choice of using Discrete Video Timings, VESA Generalized Timing
 24	  Formula, or a framebuffer specific database to set the video mode
 25
 26	- Supports a variable range of horizontal and vertical resolution, and
 27	  vertical refresh rates if the VESA Generalized Timing Formula is 
 28	  enabled.
 29
 30        - Supports color depths of 8, 16, 24 and 32 bits per pixel
 31
 32	- Supports pseudocolor, directcolor, or truecolor visuals
 33
 34        - Full and optimized hardware acceleration at 8, 16 and 24 bpp
 35
 36	- Robust video state save and restore
 37
 38        - MTRR support 
 39
 40	- Utilizes user-entered monitor specifications to automatically
 41	  calculate required video mode parameters.
 42
 43	- Can concurrently run with xfree86 running with native i810 drivers 
 44
 45	- Hardware Cursor Support
 46 
 47C.  List of available options
 48	
 49   a. "video=i810fb"  
 50	enables the i810 driver
 51
 52	Recommendation: required
 53 
 54   b. "xres:<value>"  
 55	select horizontal resolution in pixels
 56
 57	Recommendation: user preference 
 58	(default = 640)
 59
 60   c. "yres:<value>"
 61	select vertical resolution in scanlines. If Discrete Video Timings
 62	is enabled, this will be ignored and computed as 3*xres/4.  
 63
 64	Recommendation: user preference
 65	(default = 480)
 66		
 67   d. "vyres:<value>" 
 68	select virtual vertical resolution in scanlines. If (0) or none
 69	is specified, this will be computed against maximum available memory. 
 70
 71	Recommendation: do not set
 72	(default = 480)
 73
 74   e. "vram:<value>"
 75	select amount of system RAM in MB to allocate for the video memory 
 76
 77	Recommendation: 1 - 4 MB.
 78	(default = 4)
 79
 80   f. "bpp:<value>"   
 81	select desired pixel depth 
 82
 83	Recommendation: 8
 84	(default = 8)
 85
 86   g. "hsync1/hsync2:<value>" 
 87	select the minimum and maximum Horizontal Sync Frequency of the 
 88	monitor in KHz.  If a using a fixed frequency monitor, hsync1 must 
 89	be equal to hsync2. 
 90
 91	Recommendation: check monitor manual for correct values
 92	default (29/30)
 93
 94   h. "vsync1/vsync2:<value>" 
 95	select the minimum and maximum Vertical Sync Frequency of the monitor
 96	in Hz. You can also use this option to lock your monitor's refresh 
 97	rate.
 98
 99	Recommendation: check monitor manual for correct values
100	(default = 60/60)
101
102	IMPORTANT:  If you need to clamp your timings, try to give some 
103	leeway for computational errors (over/underflows).  Example: if 
104	using vsync1/vsync2 = 60/60, make sure hsync1/hsync2 has at least
105	a 1 unit difference, and vice versa.
106
107   i. "voffset:<value>"	
108        select at what offset in MB of the logical memory to allocate the 
109	framebuffer memory.  The intent is to avoid the memory blocks
110	used by standard graphics applications (XFree86).  The default
111        offset (16 MB for a 64MB aperture, 8 MB for a 32MB aperture) will
112        avoid XFree86's usage and allows up to 7MB/15MB of framebuffer
113        memory.  Depending on your usage, adjust the value up or down, 
114	(0 for maximum usage, 31/63 MB for the least amount).  Note, an 
115	arbitrary setting may conflict with XFree86.
116
117	Recommendation: do not set
118	(default = 8 or 16 MB)
119      
120   j. "accel" 
121	enable text acceleration.  This can be enabled/reenabled anytime 
122	by using 'fbset -accel true/false'. 
123
124	Recommendation: enable
125	(default = not set) 
126
127   k. "mtrr" 
128	enable MTRR.  This allows data transfers to the framebuffer memory
129	to occur in bursts which can significantly increase performance.
130	Not very helpful with the i810/i815 because of 'shared memory'. 
131
132	Recommendation: do not set
133	(default = not set) 
134
135   l. "extvga"
136	if specified, secondary/external VGA output will always be enabled.
137	Useful if the BIOS turns off the VGA port when no monitor is attached.
138	The external VGA monitor can then be attached without rebooting. 
139
140	Recommendation: do not set
141	(default = not set)
142	
143   m. "sync" 
144	Forces the hardware engine to do a "sync" or wait for the hardware
145	to finish before starting another instruction. This will produce a 
146	more stable setup, but will be slower.
147
148	Recommendation: do not set
149	(default = not set)
150
151   n. "dcolor"
152        Use directcolor visual instead of truecolor for pixel depths greater
153	than 8 bpp.  Useful for color tuning, such as gamma control.
154
155	Recommendation: do not set
156	(default = not set)
157			
158D. Kernel booting
159
160Separate each option/option-pair by commas (,) and the option from its value
161with a colon (:) as in the following:
162
163video=i810fb:option1,option2:value2
164
165Sample Usage
166------------
167
168In /etc/lilo.conf, add the line:
169
170append="video=i810fb:vram:2,xres:1024,yres:768,bpp:8,hsync1:30,hsync2:55, \
171        vsync1:50,vsync2:85,accel,mtrr"
172
173This will initialize the framebuffer to 1024x768 at 8bpp.  The framebuffer
174will use 2 MB of System RAM. MTRR support will be enabled. The refresh rate 
175will be computed based on the hsync1/hsync2 and vsync1/vsync2 values.  
176
177IMPORTANT:
178You must include hsync1, hsync2, vsync1 and vsync2 to enable video modes
179better than 640x480 at 60Hz.
180
181E.  Module options
182	
183	The module parameters are essentially similar to the kernel 
184parameters. The main difference is that you need to include a Boolean value 
185(1 for TRUE, and 0 for FALSE) for those options which don't need a value. 
186
187Example, to enable MTRR, include "mtrr=1".
188
189Sample Usage
190------------
191
192Using the same setup as described above, load the module like this:
193
194	modprobe i810fb vram=2 xres=1024 bpp=8 hsync1=30 hsync2=55 vsync1=50 \
195	         vsync2=85 accel=1 mtrr=1
196
197Or just add the following to /etc/modprobe.conf
198
199	options i810fb vram=2 xres=1024 bpp=16 hsync1=30 hsync2=55 vsync1=50 \
200	vsync2=85 accel=1 mtrr=1
201
202and just do a 
203
204	modprobe i810fb
205
206
207F.  Setup
208
209	a. Do your usual method of configuring the kernel. 
210	
211	make menuconfig/xconfig/config
212
213	b. Under "Code Maturity Options", enable "Prompt for experimental/
214	   incomplete code/drivers".
215
216 	c. Enable agpgart support for the Intel 810/815 on-board graphics.
217	   This is required.  The option is under "Character Devices"
218
219	d. Under "Graphics Support", select "Intel 810/815" either statically
220	   or as a module.  Choose "use VESA GTF for video timings"  if you 
221	   need to maximize the capability of your display.  To be on the 
222	   safe side, you can leave this unselected.  
223  
224        e. If you want a framebuffer console, enable it under "Console 
225	   Drivers"
226
227	f. Compile your kernel. 
228	  	
229	g. Load the driver as described in section D and E.
230	
231	Optional:	
232	h.  If you are going to run XFree86 with its native drivers, the 
233	    standard XFree86 4.1.0 and 4.2.0 drivers should work as is.
234            However, there's a bug in the XFree86 i810 drivers.  It attempts 
235	    to use XAA even when switched to the console. This will crash
236	    your server. I have a fix at this site:  
237	    
238	    http://i810fb.sourceforge.net.  
239
240	    You can either use the patch, or just replace 
241	    
242            /usr/X11R6/lib/modules/drivers/i810_drv.o
243
244	    with the one provided at the website. 	
245
246	i.  Try the DirectFB (http://www.directfb.org) + the i810 gfxdriver
247	    patch to see the chipset in action (or inaction :-).
248
249G.  Acknowledgment:
250	
251	1.  Geert Uytterhoeven - his excellent howto and the virtual
252                                 framebuffer driver code made this possible.
253
254	2.  Jeff Hartmann for his agpgart code.  
255
256	3.  The X developers.  Insights were provided just by reading the
257	    XFree86 source code.
258
259	4.  Intel(c).  For this value-oriented chipset driver and for
260            providing documentation.
261
262	5. Matt Sottek.  His inputs and ideas  helped in making some
263	optimizations possible.
264
265H.  Home Page:
266
267	A more complete, and probably updated information is provided at
268http://i810fb.sourceforge.net.
269
270###########################
271Tony
272