[ddccontrol-users] Re: [ddccontrol-devel] DDCcontrol and Intel 82865G Integrated Graphics Controller

[Nicolas B. <ni...@bo...>]

Hi Will,

Thanks for the infos, we'll see if we can do something with them.

Could you please send me the output of "lspci -v -v"?

Best regards,

Nicolas

On Sat, 2005-07-23 at 17:23 -0500, William Hollingworth wrote:
> Hi Nicolas
> 
> Great to see Intel support I have tried it on a couple of machines and in 
> general it works great with  my 82865G Integrated Graphics Controller and 
> an analog DSUB15 connector.
> 
> However this system has an Intel specific AGP daughter card (it's not a 
> full video card, just DVI drivers) that has DVI output.
> 
> With a monitor connected to that card I can't communicate with the display 
> using either GPIOA or GPIOB. Communications is always routed to the DSUB15 
> connector.
> 
> I had a look through the Intel docs and it seems there is MDDC_CLK and 
> MDDC_DATA (also MDVI_CLK and MDVI_DATA) for communicating with the monitor 
> on the DVI connector. Info as follows:
> -------------------------------
> DDC (Display Data Channel)
> The multiplexed digital display interface uses the MDVI_CLK and MDVI_DATA 
> signals to interrogate the panel. The GMCH supports the DDC2B protocol to 
> initiate the transfer of EDID data. The multiplexed digital display 
> interface uses the M_I2C bus to interrogate the external
> transmitter. A third set of signals (MDDC_CLK and MDDC_DATA) is available 
> for a variety of
> purposes. They can be used as a second DDC pair when two TMDS transmitters 
> are used, or as a second I2C pair if there are multiple devices (e.g., PROM 
> and DVO device) that need I2C and there is a speed or addressing conflict.
> 
> The GMCH implements a hardware GMBus controller that can be used to control 
> these signals.
> This allows higher speed transactions (up to 400 kHz) on theses lines than 
> was allowed with
> previous software centric 'bit-bashing' techniques.
> -------------------------------
> 
> However I haven't been able to find any programming info (register offsets 
> etc.) for this anywhere.
> 
> Has anyone got any info on this?
> 
> Thanks
> 
> Will

-- 
Nicolas Boichat <ni...@bo...>