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8.4 KiB
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288 lines
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================================
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Intel 810/815 Framebuffer driver
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================================
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Tony Daplas <adaplas@pol.net>
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http://i810fb.sourceforge.net
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March 17, 2002
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First Released: July 2001
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Last Update: September 12, 2005
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A. Introduction
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===============
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This is a framebuffer driver for various Intel 810/815 compatible
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graphics devices. These include:
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- Intel 810
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- Intel 810E
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- Intel 810-DC100
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- Intel 815 Internal graphics only, 100Mhz FSB
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- Intel 815 Internal graphics only
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- Intel 815 Internal graphics and AGP
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B. Features
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============
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- Choice of using Discrete Video Timings, VESA Generalized Timing
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Formula, or a framebuffer specific database to set the video mode
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- Supports a variable range of horizontal and vertical resolution and
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vertical refresh rates if the VESA Generalized Timing Formula is
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enabled.
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- Supports color depths of 8, 16, 24 and 32 bits per pixel
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- Supports pseudocolor, directcolor, or truecolor visuals
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- Full and optimized hardware acceleration at 8, 16 and 24 bpp
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- Robust video state save and restore
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- MTRR support
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- Utilizes user-entered monitor specifications to automatically
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calculate required video mode parameters.
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- Can concurrently run with xfree86 running with native i810 drivers
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- Hardware Cursor Support
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- Supports EDID probing either by DDC/I2C or through the BIOS
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C. List of available options
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=============================
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a. "video=i810fb"
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enables the i810 driver
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Recommendation: required
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b. "xres:<value>"
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select horizontal resolution in pixels. (This parameter will be
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ignored if 'mode_option' is specified. See 'o' below).
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Recommendation: user preference
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(default = 640)
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c. "yres:<value>"
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select vertical resolution in scanlines. If Discrete Video Timings
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is enabled, this will be ignored and computed as 3*xres/4. (This
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parameter will be ignored if 'mode_option' is specified. See 'o'
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below)
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Recommendation: user preference
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(default = 480)
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d. "vyres:<value>"
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select virtual vertical resolution in scanlines. If (0) or none
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is specified, this will be computed against maximum available memory.
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Recommendation: do not set
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(default = 480)
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e. "vram:<value>"
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select amount of system RAM in MB to allocate for the video memory
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Recommendation: 1 - 4 MB.
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(default = 4)
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f. "bpp:<value>"
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select desired pixel depth
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Recommendation: 8
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(default = 8)
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g. "hsync1/hsync2:<value>"
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select the minimum and maximum Horizontal Sync Frequency of the
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monitor in kHz. If using a fixed frequency monitor, hsync1 must
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be equal to hsync2. If EDID probing is successful, these will be
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ignored and values will be taken from the EDID block.
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Recommendation: check monitor manual for correct values
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(default = 29/30)
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h. "vsync1/vsync2:<value>"
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select the minimum and maximum Vertical Sync Frequency of the monitor
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in Hz. You can also use this option to lock your monitor's refresh
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rate. If EDID probing is successful, these will be ignored and values
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will be taken from the EDID block.
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Recommendation: check monitor manual for correct values
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(default = 60/60)
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IMPORTANT: If you need to clamp your timings, try to give some
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leeway for computational errors (over/underflows). Example: if
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using vsync1/vsync2 = 60/60, make sure hsync1/hsync2 has at least
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a 1 unit difference, and vice versa.
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i. "voffset:<value>"
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select at what offset in MB of the logical memory to allocate the
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framebuffer memory. The intent is to avoid the memory blocks
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used by standard graphics applications (XFree86). The default
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offset (16 MB for a 64 MB aperture, 8 MB for a 32 MB aperture) will
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avoid XFree86's usage and allows up to 7 MB/15 MB of framebuffer
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memory. Depending on your usage, adjust the value up or down
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(0 for maximum usage, 31/63 MB for the least amount). Note, an
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arbitrary setting may conflict with XFree86.
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Recommendation: do not set
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(default = 8 or 16 MB)
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j. "accel"
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enable text acceleration. This can be enabled/reenabled anytime
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by using 'fbset -accel true/false'.
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Recommendation: enable
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(default = not set)
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k. "mtrr"
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enable MTRR. This allows data transfers to the framebuffer memory
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to occur in bursts which can significantly increase performance.
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Not very helpful with the i810/i815 because of 'shared memory'.
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Recommendation: do not set
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(default = not set)
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l. "extvga"
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if specified, secondary/external VGA output will always be enabled.
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Useful if the BIOS turns off the VGA port when no monitor is attached.
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The external VGA monitor can then be attached without rebooting.
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Recommendation: do not set
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(default = not set)
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m. "sync"
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Forces the hardware engine to do a "sync" or wait for the hardware
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to finish before starting another instruction. This will produce a
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more stable setup, but will be slower.
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Recommendation: do not set
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(default = not set)
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n. "dcolor"
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Use directcolor visual instead of truecolor for pixel depths greater
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than 8 bpp. Useful for color tuning, such as gamma control.
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Recommendation: do not set
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(default = not set)
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o. <xres>x<yres>[-<bpp>][@<refresh>]
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The driver will now accept specification of boot mode option. If this
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is specified, the options 'xres' and 'yres' will be ignored. See
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Documentation/fb/modedb.rst for usage.
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D. Kernel booting
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=================
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Separate each option/option-pair by commas (,) and the option from its value
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with a colon (:) as in the following::
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video=i810fb:option1,option2:value2
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Sample Usage
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------------
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In /etc/lilo.conf, add the line::
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append="video=i810fb:vram:2,xres:1024,yres:768,bpp:8,hsync1:30,hsync2:55, \
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vsync1:50,vsync2:85,accel,mtrr"
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This will initialize the framebuffer to 1024x768 at 8bpp. The framebuffer
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will use 2 MB of System RAM. MTRR support will be enabled. The refresh rate
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will be computed based on the hsync1/hsync2 and vsync1/vsync2 values.
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IMPORTANT:
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You must include hsync1, hsync2, vsync1 and vsync2 to enable video modes
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better than 640x480 at 60Hz. HOWEVER, if your chipset/display combination
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supports I2C and has an EDID block, you can safely exclude hsync1, hsync2,
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vsync1 and vsync2 parameters. These parameters will be taken from the EDID
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block.
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E. Module options
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==================
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The module parameters are essentially similar to the kernel
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parameters. The main difference is that you need to include a Boolean value
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(1 for TRUE, and 0 for FALSE) for those options which don't need a value.
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Example, to enable MTRR, include "mtrr=1".
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Sample Usage
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------------
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Using the same setup as described above, load the module like this::
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modprobe i810fb vram=2 xres=1024 bpp=8 hsync1=30 hsync2=55 vsync1=50 \
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vsync2=85 accel=1 mtrr=1
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Or just add the following to a configuration file in /etc/modprobe.d/::
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options i810fb vram=2 xres=1024 bpp=16 hsync1=30 hsync2=55 vsync1=50 \
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vsync2=85 accel=1 mtrr=1
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and just do a::
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modprobe i810fb
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F. Setup
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=========
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a. Do your usual method of configuring the kernel
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make menuconfig/xconfig/config
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b. Under "Code maturity level options" enable "Prompt for development
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and/or incomplete code/drivers".
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c. Enable agpgart support for the Intel 810/815 on-board graphics.
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This is required. The option is under "Character Devices".
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d. Under "Graphics Support", select "Intel 810/815" either statically
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or as a module. Choose "use VESA Generalized Timing Formula" if
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you need to maximize the capability of your display. To be on the
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safe side, you can leave this unselected.
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e. If you want support for DDC/I2C probing (Plug and Play Displays),
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set 'Enable DDC Support' to 'y'. To make this option appear, set
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'use VESA Generalized Timing Formula' to 'y'.
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f. If you want a framebuffer console, enable it under "Console
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Drivers".
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g. Compile your kernel.
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h. Load the driver as described in sections D and E.
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i. Try the DirectFB (http://www.directfb.org) + the i810 gfxdriver
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patch to see the chipset in action (or inaction :-).
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G. Acknowledgment:
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===================
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1. Geert Uytterhoeven - his excellent howto and the virtual
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framebuffer driver code made this possible.
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2. Jeff Hartmann for his agpgart code.
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3. The X developers. Insights were provided just by reading the
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XFree86 source code.
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4. Intel(c). For this value-oriented chipset driver and for
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providing documentation.
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5. Matt Sottek. His inputs and ideas helped in making some
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optimizations possible.
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H. Home Page:
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==============
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A more complete, and probably updated information is provided at
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http://i810fb.sourceforge.net.
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Tony
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