This is still on the trio64, which has improved significantly over the previous commits, however, one more bug has been found, namely when a fullscreen DOS box is triggered on win3.1 with trio64 drivers in any bpp, it would basically make the percentage down to around 30% and hang. (And in any machine)
Note: This doesn't happen when the DOS box is in windowed mode.
Update: it's caused by the force busy flag in the code.