Comment 44 for bug 150709

The issue here is that the monitor is returning EDID that the driver does not seem to recognize properly (parse-edid seems not to comprehend it either), as it doesn't pick up the correct preferred mode. Likely the monitor is simply emitting invalid edid information.

Since the DDC output seems more valid, perhaps the right workaround is to use Option "IgnoreEDID".

Please run `sudo get-edid > edid.dat` and attach that file to this bug report.

Also, if possible, could you test the monitor with a different computer (using -intel or -nv graphics if possible), and/or try a different model of monitor with your Radeon 7500, and report if you can reproduce the issue with any of those combinations.