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63 lines
2.0 KiB
63 lines
2.0 KiB
20 years ago
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Kernel driver i2c-voodoo3
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Supported adapters:
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* 3dfx Voodoo3 based cards
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* Voodoo Banshee based cards
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Authors:
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Frodo Looijaard <frodol@dds.nl>,
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Philip Edelbrock <phil@netroedge.com>,
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Ralph Metzler <rjkm@thp.uni-koeln.de>,
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Mark D. Studebaker <mdsxyz123@yahoo.com>
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Main contact: Philip Edelbrock <phil@netroedge.com>
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The code is based upon Ralph's test code (he did the hard stuff ;')
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Description
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-----------
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The 3dfx Voodoo3 chip contains two I2C interfaces (aka a I2C 'master' or
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'host').
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The first interface is used for DDC (Data Display Channel) which is a
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serial channel through the VGA monitor connector to a DDC-compliant
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monitor. This interface is defined by the Video Electronics Standards
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Association (VESA). The standards are available for purchase at
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http://www.vesa.org .
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The second interface is a general-purpose I2C bus. The intent by 3dfx was
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to allow manufacturers to add extra chips to the video card such as a
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TV-out chip such as the BT869 or possibly even I2C based temperature
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sensors like the ADM1021 or LM75.
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Stability
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---------
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Seems to be stable on the test machine, but needs more testing on other
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machines. Simultaneous accesses of the DDC and I2C busses may cause errors.
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Supported Devices
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-----------------
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Specifically, this driver was written and tested on the '3dfx Voodoo3 AGP
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3000' which has a tv-out feature (s-video or composite). According to the
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docs and discussions, this code should work for any Voodoo3 based cards as
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well as Voodoo Banshee based cards. The DDC interface has been tested on a
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Voodoo Banshee card.
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Issues
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------
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Probably many, but it seems to work OK on my system. :')
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External Device Connection
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--------------------------
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The digital video input jumpers give availability to the I2C bus.
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Specifically, pins 13 and 25 (bottom row middle, and bottom right-end) are
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the I2C clock and I2C data lines, respectively. +5V and GND are probably
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also easily available making the addition of extra I2C/SMBus devices easy
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to implement.
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