[vbox-dev] Problem in 8042

Frank Mehnert Frank.Mehnert at Sun.COM
Wed Sep 24 05:21:08 PDT 2008


On Saturday 13 September 2008, Felix Kaiser wrote:
> 8042 hardware implementations provide the value at data port 0x60 after
> read for a small time, so if the port is read again within that time,
> the read value will be the same. The 8042 emulation provided by
> VirtualBox clears that value too fast, seems to be cleared immediately
> after read. Chained 8042 interrupt handlers (keyboard 1, mouse 12) may
> read different values within one interrupt shot resulting in problems
> especially with extended keys and handling key releases. Chained 8042
> handlers are commonly used by DOS applications for handling special keys
> and providing hot keys. Having both PS/2 mouse and keyboard may also
> result in handling mouse data in the keyboard interrupt. The problem
> could be solved by providing the value at the data port unless receiving
> EOI if interrupts are enabled.
> At moment many DOS applications doesn't work correctly.
> Please let me know if you want to know something more.

Sorry for the late answer and thanks for the hint. Do you have a pointer
for the 8042 specification?

Kind regards,

Dr.-Ing. Frank Mehnert    Sun Microsystems    http://www.sun.com/
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