I had the same issue with X server crashing on SuperMicro AS-4124GS-TNR which has AST 2500 as well.
I was able to resolve by disabling gl-related modules and the modesetting driver.
Here are the instuctions: https://gist.github.com/sergey-cheperis/530666bc5d7064185ab72bfcaeb19ff1
Hope this helps.