08693: neocdz [aof]: Audio corruption after reaching bonus stage

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08693	Sound	Critical (emulation)	Always	Jul 1, 2023, 20:05	Nov 7, 2023, 06:58

Tester	Foxhack	View Status	Public	Platform	MAME (Official Binary)
Assigned To	dink	Resolution	Fixed	OS	Windows 10/11 (64-bit)
Status [?]	Resolved			Driver	neogeo/neogeocd.cpp
Version	0.256	Fixed in Version	0.261	Build	64-bit
		Fixed in Git Commit	b53e835	Github Pull Request #	#11713

Summary	08693: neocdz [aof]: Audio corruption after reaching bonus stage
Description	When you beat the second opponent, you go to a bonus stage where you can gain extra life, energy, or learn a special move. The bonus stage takes a long time to actually load (compared to hardware recordings on nicovideo) and when it does, the audio samples used by the game become corrupt. Examples: The "Bottle cut" bonus stage replaces the bottle cut sounds with explosions; "Stage 3: China Town" ends abruptly with the "Town" replaced with a grunt; "Round 1" in the next fight has the "1" replaced with a thud The "bounce against the wall" sound is replaced with a slicing sound effect This audio corruption remains present even if you lose and start a new game from the beginning or load a saved game from backup RAM. Resetting the machine fixes the corruption, and loading from backup RAM to a later stage doesn't show the same issues. So something about that bonus stage load screen is causing the audio corruption.
Steps To Reproduce	Play game normally Reach the bonus stages
Additional Information	https://www.nicovideo.jp/watch/sm31295794 is a video of the game being played in actual hardware. 6:18 shows the load screen and can be used to verify the correct load time, plus that it doesn't have the audio corruption issue.
Github Commit

Flags
Regression Version
Affected Sets / Systems	neocdz [aof]

Attached Files

No.21607 dink Tester Jul 3, 2023, 14:28	The game barfs on the lc8951 registers at this point. Strangely, the affected registers can be influenced with the last button press(es) before the bonus stage loads. The issue usually causes an incorrectly-sized dma request while loading the adpcm data from cd iirc.
No.21821 Foxhack Tester Nov 7, 2023, 03:58	It looks like https://github.com/mamedev/mame/pull/11713 fixed this. :D
No.21822 Robbbert Senior Tester Nov 7, 2023, 06:57	I have no way of testing this, so I'll resolve this on your word.