MEGAMID hangs while resetting the SB DSP if used with the /sbmidi program argument.

[barotto]

After the Sound Blaster DSP reset, MEGAMID reads the DMA channel 0's current count register (port 0x01) to see if its value is 0, otherwise it waits indefinitely.

The PS/1 BIOS POST procedure tests the DMA controller writing all its registers with the 0xAA value without clearing them afterwards, so when MEGAMID reads port 0x01 looking for 0 it ends up hanging.

Verified also on DOSBox, which won't hang as it starts with all DMA registers cleared.

Not verified on real hardware (I need a Sound Blaster) but AFAIK the DMA controller won't clear its channels' registers on RESET so I expect MEGAMID to hang on a real PS/1 too.

This is a MEGAMID's bug which manifests itself on the PS/1, so everything "works" as intended.