[Open-graphics] Re: DDC injection box Re: Boot-time video mode

[Timothy Miller]

On 8/31/06, Jack Carroll <mykrowatt at comcast.net> wrote:

>         One question: can it get its power from the OGC1, if the display
> doesn't send any power up the cable?

I'm pretty sure that DDC supplies power from the graphics card.

>         (All of this assumes that OGC1 and its BIOS actually implement EDID.
> Last remarks I saw implied you were leaning that way, but it wasn't final.)

I think EDID should be supported without question.

>         Regarding the SPI tools, I wonder where your thinking has evolved to
> since we last threw ideas around?
>         Does it simplify the ASIC and the board if all devices on the SPI
> port are required to emulate the serial EEPROM?

You may have no choice but to include an SPI PROM on the external
board, because of clock speeds.

>         If the EEPROM is big enough, can it supply everything the ASIC needs
> to configure itself at power-up?

They're really cheap.  Put a big one on there.

>         Can an external EEPROM supply a pre-configured video mode program
> along with everything else it stores?  (If so, then an intelligent SPI tool
> could compute a mode program and impersonate an EEPROM.  That shouldn't
> require any features to be added to the ASIC, beyond providing a chip select
> for an external EEPROM tool.)

This sounds like a good solution.