But a crash happening anyway with DRI3 and Xorg not using the GPU directly is exactly the original issue I posted this bug report trying to fix. And I just finished testing without any of my own explicit options for amdgpu: no DRI3, no Ignore (and it the DRI_PRIME stuff I was doing still works fine, so you were right that those options had no point), and it's still crashing unless AutoAddGPU is turned off. So, I'll be grabbing that debug output in debian now.
But a crash happening anyway with DRI3 and Xorg not using the GPU directly is exactly the original issue I posted this bug report trying to fix. And I just finished testing without any of my own explicit options for amdgpu: no DRI3, no Ignore (and it the DRI_PRIME stuff I was doing still works fine, so you were right that those options had no point), and it's still crashing unless AutoAddGPU is turned off. So, I'll be grabbing that debug output in debian now.