07044: cpc6128f: Input stutter with lag for keyboard input

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07044	DIP/Input	Major	Always	Jul 10, 2018, 21:40	Jul 17, 2018, 21:25

Tester	Gryzor1363	View Status	Public	Platform	MAME (Unofficial Binary)
Assigned To		Resolution	Open	OS	Windows Vista/7/8 (64-bit)
Status [?]	Acknowledged			Driver	amstrad/amstrad.cpp
Version	0.199	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07044: cpc6128f: Input stutter with lag for keyboard input
Description	Pressing a key in-game results in a "stuttered" response with lag. For instance, keeping the "O" or "P" keys pressed for 3-5 secs (often the default bind in many CPC titles for movement to the left and right respectively) results in the character staying idle for 1-2 seconds, and then responding by brief, successive bits of movement lasting for 0.5 secs in the inputted direction instead, with pauses of approximately 0.25-0.5 secs between each. Behavior continues for a 1-2 sec interval after you have stopped pressing the desired button, hinting at some buffer effect. In brief, constant input results in a delayed, interrupted feedback. Here is a list of games where there is such stutter upon loading that I have tested so far : Savage Renegade Gryzor Astro Marine Corps Robocop Batman The Movie Ghostbusters II ... and more than a dozen other titles, all exclusively in floppy dump versions, including non-cracked and official ones, both from standalone and compilation releases. No tape versions tested. I consequently suspect it could be a generic dysfunction irrespective of the title, at least for floppy drive emulation, though obviously I'm no expert. I am aware of and have gone through other tickets mentioning no input at all after loading .dsk images, but I did not recognize that particular pattern there. Indeed issue might or might not be related or linked to this ticket http://mametesters.org/view.php?id=6247, so I thought I could make a reference here just in case it triggers useful attention. Thanks, -G
Steps To Reproduce	1 - Boot the cpc6128f machine. 2 - Load any .dsk file via the browser with the standard run"<game executable> command. So far, no issues with input should be perceptible and keyboard input should respond normally. 3 - Once the game is loaded, start a playthrough in keyboard mode, by voluntarily not choosing joystick mode even when possible. Upon startup, described behavior should be obvious, for any key bindings relying on the keyboard, should they be default or user-defined.
Additional Information	Bug reported with latest MAMUI64 v0.199. Reproduced with versions dating as far back as MAMEUI64 0.193.
Github Commit

Flags
Regression Version
Affected Sets / Systems	cpc6128f

Attached Files

No.15266 Gryzor1363 Tester Jul 12, 2018, 14:06	Interstingly, one possible workaround is to rely on emulated Joystick inputs, and choosing joystick input through in-game menus when it is possible. Doing so bypasses this erratic behavior and responds normally. It is specifically apparent in Renegade, which uses a combination of the Joystick + Keyboard for control : player movement here is smooth since it relies on emulated Joystick binds, but punches/kicks are not, and display the same reported symptoms, responding randomly and with delay, thus provoking a near-unplayable situation.
No.15273 ICEknight Tester Jul 13, 2018, 23:30	Is the Keyboard Mode set to "Natural", by any chance? I think that somebody told me a while ago that a delay was intentionally added to it, so that it would make typing easier... But since many systems already have their own delays, maybe it could be made optional just for those cases where it may be useful?
No.15281 Gryzor1363 Tester Jul 17, 2018, 21:25	Thanks for asking. After verification it happened to be on "Natural" indeed. When changing to "Emulated", issue doesn't manifest anymore. I can hereby confirm by repeated testing that issue described in this ticket only applies to "Natural" keyboard mode.