[Openchrome-devel] Fix vt1625 output sensing

Harry de Boer harry at ijscoboer.nl
Thu Nov 22 06:26:52 PST 2012

Hi Xavier,

thanks for the pointers, I did not know there were two variants. I have 
the VT1625 variant without the 'S' (that is good, it means we can test 

The VT1625S seems to have status bits 4 and 5 always read 0 which on the 
VT1625 would mean an S-Video cable is connected ( I assume your board 
with the VT1625 does not have an S-Video connector?). So we should 
distinguish between them, but I am not sure yet how... If you could 
confirm that this patch it reports an S-Video connection while it's not 
there, we know for sure.

Willem: thanks for the reply, I hope I can figure it out! If you could 
test if the detection works properly for you that would be good.

About subscribing: the new mailing list tells me: "Your subscription 
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On 22-11-12 14:28, Xavier Bachelot wrote:
> Hi Harry,
> On 11/22/2012 02:01 PM, Harry de Boer wrote:
>> Hi,
>> I recently upgraded my Via machine to the latest Ubuntu and I couldn't
>> get my tv-output to work again. Last night I decided to dive into the
>> code a bit. The first thing I noticed was that vt1625 output sensing
>> seemed broken. Attached is a patch that should fix that.
>> I haven't got it working again yet so there's more to be done. If there
>> is anything I should know before continuing or have any tips please let
>> me know.
> Thanks for the patch. There's someone with issue with the TV out on an 
> EX board on the -users mailing list and he has trouble with probing 
> the TV out too, so it comes right to the point ;-)
> There are 2 variant of the VT1625 (VT1625 and VT1625S) out in the wild 
> and it seems there are subtle differences between them. One of the 
> difference is one has 4 DACs and the other has 6. They are sharing the 
> same idea so I don't know of a good way to tell one from the other.
> Fortunately, there are datasheets available for both, it might help 
> you get the TV out working.
> See http://www.openchrome.org/trac/wiki/Development#TVencoders
> Out of curiosity, I do have an EX board too (for testing purpose) and 
> mine is using a VT1625S. What's the flavor on yours ?
>> A little about me: I am a computing science student from the
>> Netherlands, I have a Via EPIA EX10000EG Mini-ITX board which has a
>> CX700 chip. It's mainly used as a server and for its tv-out.
> Glad to meet you and welcome on board :-)
>> Cheers,
>> Harry
>> NB, the mailing list link on the openchrome.org front page is still
>> linking to the old mailing lists, I first sent this message there by
>> accident.
> Thanks for the heads up, I'll fix that tonight. Both the old mailing 
> lists and new ones are still working though, so we've got 2 copies of 
> your mail. I've dropped the first one from the queue.
> Btw, consider subscribing to the list if you don't want your mails to 
> be stuck in the moderation queue until someone let them in ;-)
> Regards,
> Xavier

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