[Openchrome-users] DVI DDC on Jetway DVI daughter-card

[Luc Verhaegen]

On Fri, May 08, 2009 at 09:45:53PM +0100, Phil Endecott wrote:
> Dear Experts,
> 
> I have a Jetway J7F2 board (CN700 based) with a DVI daughter-board that 
> has a VT1632A DVI chip on it.  I understand from the wiki that this 
> chip is not officially supported, but having enabled it in the BIOS it 
> works for me.
> 
> The only problem is that it does not appear to read DDC from the DVI 
> interface.  If I start X with only DVI connected I get a default low 
> resolution screen; if I boot with both DVI and VGA connected I get the 
> correct resolution on the DVI output.
> 
> I believe that the VT1632A doesn't have any DDC I2C functionality so my 
> guess is that the DDC I2C signals from my DVI connector are either not 
> connected at all, in which case there is obviously not much I can do, 
> or they go straight through to the motherboard and into the main 
> chipset.  In the latter case, maybe it's not difficult for the driver 
> to probe them?
> 
> I'll put a couple of X logs here:
> 
> http://chezphil.org/tmp/haiti_x_log_dvi_only
> http://chezphil.org/tmp/haiti_x_log_dvi_and_vga
> 
> Apologies if this has been discussed before; I haven't found anything 
> when searching.  Also I'd be interested to hear from anyone else using 
> one of these Jetway DVI daughter boards; I have a suspicion that mine 
> might suffer from overheating.  [If you want a laugh: earlier I 
> attempted to test my overheating theory with a can of freezer spray - 
> and picked up the Spray Glue instead.  The inside of the box is now a 
> sticky mess.  But I now know that spray glue does not conduct electricity...]
> 
> 
> Cheers,  Phil.

I own this hw, and have tested it extensively, it will be handled as 
well as possible once i transfer some of the ideas i implemented when i 
brought up the radeonhd driver to my unichrome driver. There will be 
proper detection and board support then.

For now though, my unichrome driver doesn't bring up the vt1632 
correctly yet, as i set one bit wrongly, but that, too, requires the 
correct infrastructure first.

Luc Verhaegen.
http://unichrome.sf.net/