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This question is an extension of this one. My problem is my Aspeed video card (not a gpu) ends up dectecting and using the wrong video polarity that results in an a off bound video output along a resolution the screen doesn’t recognizes.
This happens both in Xorg and the kernel virtual console and with generic video drivers as well as the official deprecated Linux Aspeed drivers. It should be noted that I didn’t had this problem with that screen the last time I used vga output with an old agp Nvidia card 15 years ago.
Neverless, the more recent Windows based official driver doesn’t have this problem. .

Based on the documentation,
how do I set the correct polarity or get the right video polarity to be detected correctly?

user2284570
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  • What is the native resolution of the display? Have you tried just specifying some or other standard resolution via video=, without any extra tweaks? (Your photo shows KDE using 1680x1050, is that correct?) Also, have you tried a different VGA cable, just in case? (I've had a few cases where old VGA cables prevented the graphics adapter from receiving EDID data from the display, and therefore from detecting the correct video mode.) – u1686_grawity Aug 21 '22 at 13:19
  • @user1686 16880 by 1050 is the native resolution as correctly detected by Linux. Otherwise, yes I tried this. As you can see with the Windows picture were it works this has no link to the hardware. This is a software driver problem. The monitor states the difference is the electrical polarity which is reversed on Windows were it works. Also edid contains no informations about polarity. – user2284570 Aug 21 '22 at 14:00

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