search

marqs85 / ossc_pro

GNU General Public License v3.0
38 stars 10 forks source link

[BUG] jumping VGA input at 800x600 and above #8

Closed arncht closed 2 months ago

arncht commented 2 months ago

Hi,

I have an issue with multiple analog VGA outputs. When the resolution is set to 800x600 and above, the screen continuously "jumps". Below this resolution, everything is fine. With some VGAs, if I change the input parameters, sometimes it's okay, but the next time it is buggy again. And with some VGAs, no matter what I do, it is always wrong.

I tried updating to the latest firmware and resetting the OSSC. The output resolution is irrelevant (anyway, I use 1440p 60Hz).

Best regards,

marqs85 commented 2 months ago

Can you try if adjusting AV1-3 sync opt -> TTL Hsync Vth helps? If not, then I'm afraid this is due to an issue in the ADC chip which is described here (with a fix that involves HW modification). So far the occurence has been limited to certain sources regardless of their output mode, though.

arncht commented 2 months ago

I've tried out some configurations, and while some cases help, there's no consistent setup. When something seems to work well, switching to another mode often results in it being wrong again. I've tested with the most popular cards of the millennium (3dfx Voodoo2, GeForce2 GTS, GeForce3), and it's completely ad hoc determining where and how it's not okay. Mostly, it's not functional; however, in some cases, it could work.

marqs85 commented 2 months ago

does the red LED stay on in A-LM mode?

marqs85 commented 2 months ago

I discovered a different issue which result to vertical jumping if H and V syncs are very closely aligned. This is on FW side and was easy to fix. Is this perhaps what you encountered instead of sync/horizontal instability which the other issue is referring to?

arncht commented 2 months ago

does the red LED stay on in A-LM mode?

No, it does not. Does it show the no sync?

arncht commented 2 months ago

I discovered a different issue which result to vertical jumping if H and V syncs are very closely aligned. This is on FW side and was easy to fix. Is this perhaps what you encountered instead of sync/horizontal instability which the other issue is referring to?

What does it mean? Most of the cases I just reset the ossc pro, then set the scaler with the fixed output and frequency (2560x1440 60hz). I do not refine anything else.

marqs85 commented 2 months ago

Can you try if this test version works for you? It fixes vertical jumping which might occur with some RGBHV sources.

arncht commented 2 months ago

I tested it from 800x600 to 1600x1200, works well! I could check it just with one problematic card, but looks ok.

Thank you, great job!