OSSC PRO: AV4 No Sync

[erazortt]

What do I need to do so that the HDMI in works? The HDMI connection works if I insert the cable directly to the display, but when I want to route the HDMI signal through the OSSC Pro, it does not get a sync. I have the Firmware 0.78.

So this works:
Geforce FX5200 DVI -> DVI to HDMI Adapter -> HDMI cable -> Display

This does not work:
Geforce FX5200 DVI -> DVI to HDMI Adapter -> HDMI cable -> OSSC Pro

• This topic was modified 2 months, 3 weeks ago by erazortt.

[BuckoA51]

Make sure HDCP is disabled, and your GPU is outputting a resolution that the OSSC Pro can definitely display (try 720p60 for starters).

[erazortt]

So apparently it works when it enters Windows, but it does not work during boot?

Using the VGA output of the same graphics cards shows the bood sequence. Also when connecting the HDMI cable directly to the display shows the boot sequence. But when the HDMI cable is connected to the OSSC Pro the boot sequence is not shown.

• This reply was modified 2 months, 3 weeks ago by erazortt.
• This reply was modified 2 months, 3 weeks ago by erazortt.

[erazortt]

Ok so I fuguerdout how to do it. I need to dump the EDID information and give it to OSSC as a custom EDID. Then it works.

I would actually suggest that this forwarding of the attached HDMI display should be a selectable option for the custom EDID.

[erazortt]

hm, apparently I was too fast to comclude. So now it does show something, but the low resolution modes are just upsacled by the graphics card and are feeded as a 1024*768 to OSSC.. That is not the right solution, since its exactly these low resolution modes I need OSSC for.

[erazortt]

So that experiment with the custom EDID, makes it appear that OSSC has something in its EDID which it presents to the graphics cards, that makes the graphics card not like to show anything at all during boot. Because when I do use the EDID I dumped from my displays as custom EDID, it does show the boot sequence, but now the graphics cards does directly outputs a scaled signal.

• This reply was modified 2 months, 3 weeks ago by erazortt.
• This reply was modified 2 months, 3 weeks ago by erazortt.

[erazortt]

Ok so I dumed the EDID of OSSC itself and I see that the lowest resolution in there is 720*400. Why are there all the lower resolutions missing? Becuase wouldn’t that be the point to upsacle those lower resolutions? Especially those resoltuions used by DOS and BIOS would be nice to have there, right?

[erazortt]

Hm, using a more sophisticated EDID editor, I now see that indeed there are more resultions saved, apparently all low established low res are also enabled, down to 640*350 which appears to be the lowest availble for EDIDs. But then I do not understand why the boot sequence is not shown…

[erazortt]

Could it be the version of the EDID? I see that verison 1.4 was defined in 2006, but the graphics card I am using is from 2003.

[marqs]

The EDID should have all modes enabled which are presented as flags. The preferred mode (1080p60) is presented as 18-byte DTD with exact timings, but most likely a card of that era just looks at given monitor range limits and during boot outputs a mode which is within those. You can try wxedid or similar to get the EDID more compatible with the card.

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