The firmware driver tried very hard to get an image out of display, even without knowing what was possible.Again while "vcdbg log msg" seems to indicate it didn't find any EDID. Where does that mode come from?
If hotplug wasn't asserted, it would try to read the edid anyway (in violation of hdmi spec).
If hotplug was asserted (including using hgdmi_force_hotplug=1) but no edid was readable, it would make up some modes that might work.
When we moved to a kernel side driver and wanted to submit it upstream, the response was these hacks were not acceptable,
and the correct solution was for users to not expect broken cables or displays to work without manual configuration
(all the firmware hacks can be achieved using cmdline.txt to force hotplug, a default hdmi mode, or even a complete working edid).
So, to answer your question, the setting "video=HDMI-A-1:720x576M@50D" was made up, and we don't do that any more.
If you want that behaviour then you are free to add that line manually to cmdline.txt.
Or you can try to fix the underlying problem to make the edid readable (often, just switch to a hdmi cable that works).
Statistics: Posted by dom — Mon Jul 15, 2024 11:14 am