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ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07644 DIP/Input Minor Always May 6, 2020, 09:36 Jul 25, 2020, 15:20
Tester Klez View Status Public Platform MAME (Official Binary)
Assigned To sz72 Resolution Fixed OS MacOS X
Status [?] Resolved Driver
Version 0.220 Fixed in Version 0.223 Build 64-bit
Fixed in Git Commit Github Pull Request #
Summary MESS-specific 07644: pcpci: Serial port mouse [HLE] movement/clicks creates bogus input in emulated Ms-dos
Description In the driver "pcipc" you can choose different HLE serial mouses, but all of them create strange input like keypreses(?) that end crashing the emulated OS with stack overflow. See attached screenshots showing weird input when mouse is moved or clicked in MSDOS 6.
This bug is present since many versions ago, not a recent regression. The oldest build that i´ve could test is v.203
My computer is running OSX, so i guess the input backend from my real mouse is SDL2

This happens with all supported mouses:
 -serport0 logitech_mouse
 -serport0 microsoft_mouse
 -serport0 msystems_mouse
 -serport0 wheel_mouse
Steps To Reproduce Start "pcipc" driver with a floppy bootdisk image with msdos and and optionally choose a mouse model. You can download a msdos bootdisk here:

By default, pcipc driver uses "microsoft_mouse"

# mame pcipc -serport0 microsoft_mouse -flop1 bootdisk.ima

When dos is running, simply move your mouse or click primary/secondary button. Spurious input will appear and sometimes hang the emulated operative system with stack overflow.
Additional Information
Github Commit
Regression Version
Affected Sets / Systems pcpci
Attached Files
png file icon pcipc.png (7,255 bytes) May 6, 2020, 09:36 Uploaded by Klez
Weird input when using mouse
png file icon pcipc2.png (8,905 bytes) May 6, 2020, 09:37 Uploaded by Klez
msdos crashed by simply moving mouse
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Senior Tester
May 10, 2020, 03:10
I've had this issue with a number of the PC drivers, making them almost useless.
User avatar
May 10, 2020, 11:07
This bug is happening even if you start without any serial devices conected. Mouse input is still appearing, crashing emulated OS. If there is not an emulated serial mouse connected, how is this spurious input generated from my real mouse?

# mame64 pcipc -serport0 "" -serport1 "" -board4:fdc37c93x:lpt:centronics "" -flop1 bootdisk.ima -verbose

Crashes mame64 with "Caught unhandled exception" The verbose log does not show any other related info