Horun wrote on 2020-09-08, 02:39:
darry wrote on 2020-09-08, 02:09:
I had an interesting turn of events today . I tried my Zotac GTX750 Ti and my spare Gigabyte GTX750 Ti (that I managed to dig out) and tried both of them connected to my OSSC . The OSSC detects their VGA out as 806p on boot , but I am unable to get a picture through the OSSC's HDMI out on either my Philips 252B9 or my Cam Link 4K capture card . If I connect either GTX750 Ti card to the 252B9's VGA port directly, it works fine .
I tested my OSSC with VGA input up to 1600x1200@60Hz with my Voodoo 3, among other cards, without any issue .
Does anybody have any ideas ?
I do not have an OSSC yet so do not know what 806p means, but could be HDCP handshaking or something else Video BIOS related. Perhaps the cards are trying to connect first at max res and not getting the proper feedback like you mentioned before. Have you tried the same trick you told me ? Hook it up, boot it up then switch cable. Never mind am sure you already tried that.
When displaying 806p, the OSSC was receiving 1024x768 because the PC had booted into Windows . When I boot into DOS, I get 449p (probably the total number vertical of lines including active, porches and sync pulse) .
I also found the cause of the issue. It was the HDMI switch that I am using between the OSSc and the monitor ! For some reason, this switch that has no issues with all kinds of oddball resolutions generated by the OSSC from an FX 5900 or a Voodoo 3 somehow barfs when near identical resolutions are sent to it by the OSSC as processed from either of my GTX750 Ti cards .
Anyway, once I eliminated the switch:
a) I can confirm that a GTX750 Ti does not upscale to monitor native resolution over VGA when connected to an OSSC (probably due to lack of EDID), so same behaviour as cde's GTX960
b) I can confirm that a GTX750 Ti upscales (probably line-doubles first) 320x200 to 720x400 when outputting through VGA to the OSSC, so same behaviour as cde's GTX960 .
1440x800
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1280x800
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I am curious as to the Nvidia generation where the behaviour described in point b began .
EDIT : I am also curious as to whether Nvidia actually ever documented the behaviour in point b . Before cde noticed it, I had never heard about it .