On Sat, May 25, 2019 at 06:56:54PM -0600, Benjamin Slade wrote: > How do I determine what the appropriate EDID should be?
The kernel exposes the EDID block of connected monitors at /sys/class/drm/*/edid You can feed that to edid-decode and see if it makes sense, e.g. is the manufacturer string right? Does it show the video modes you expect? (Maybe you can plug in the monitor through your HDMI-to-VGA contraption and get the EDID that way? I've no idea if that'll pass through the monitors EDID, or if you'll get some synthetic data block from the digital-to-analog converter chip. I've no idea how HDMI-to-VGA adapters work. Are there HDMI-to-DVI cables you could try?) > And how do I go about loading it into RAM after boot? This is painful, especially the part where you maybe have to bake the EDID file into your initramfs under certain underspecified circumstances: https://wiki.archlinux.org/index.php/kernel_mode_setting#Forcing_modes_and_EDID (Note: you need the binary EDID file, not the decoded output you get from edid-decode, or the hex-encoded string you get from xrandr --props.) The part where you specify the EDID filename on the kernel command line is also fun -- it means a reboot for every test. Eh. (It's also The Future, because Wayland compositors don't generally allow you to override monitor sync ranges or provide custom mode timings, so all the hardware workarounds have to be done via a custom EDID.) Regards, Marius Gedminas -- TCP_UP - The 16-bit TCP Urgent Pointer, encoded as the hex representation of the value of the field. The hex string MUST be capitalized since it is urgent. -- RFC 3093
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