Comment 328 for bug 1801540

That's a good discovery. This change makes sense, as the different of PRESET_ATI_SB from PRESET_AMD_SB is about the position reporting. ATI_SB uses the legacy LPIB register read while AMD_SB uses the position buffer table.
This could be verified by changing position_fix module option: 1 is LPIB and 2 is position buffer.

If we can confirm that this change generally improves the behavior, I can merge the fix quickly to the upstream. Can anyone else check it?