07314: mjikaga: Game boots and immediately gets stuck at a white screen

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07314	Crash/Freeze	Major	Always	May 2, 2019, 07:24	May 6, 2019, 16:24

Tester	Osso	View Status	Public	Platform	MAME (Official Binary)
Assigned To	Osso	Resolution	Fixed	OS	Windows 10 (64-bit)
Status [?]	Resolved			Driver	misc/homedata.cpp
Version	0.209	Fixed in Version	0.210	Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07314: mjikaga: Game boots and immediately gets stuck at a white screen
Description	Since 0.206 the game doesn't work anymore, getting stuck at a white screen.
Steps To Reproduce	Just load the game.
Additional Information	In the 0.206 dev cycle there was a pretty big update to the driver which may be the regression, though I haven't verified it yet: https://git.redump.net/mame/commit/?id=69cb8a001b01364caa27b47ac04744ce274aa5bc
Github Commit

Flags
Regression Version	0.206
Affected Sets / Systems	mjikaga

Attached Files

No.16399 Tafoid Administrator May 2, 2019, 09:17	Can confirm day of regression lines up with linked commit above (January 18, 2019)
No.16401 Osso Moderator May 2, 2019, 10:13	It appears using the latches instead of the old way is causing data not to be read in time. Reverting it fixes this, but it's obviously not the way to go.
No.16435 Osso Moderator May 6, 2019, 12:49 edited on: May 6, 2019, 12:53	It can also be worked-around by setting the maincpu and the audiocpu to perfect quantum, but it causes a 50% performance loss against 0.205. EDIT: config.m_minimum_quantum = attotime::from_hz(60000); seems to do the trick and not to cost too much in performance. I guess I'll commit this later.