REG: Device Driver Entries, PART 2--Mouse/Keyboard Driver

ID: Q102989

The information in this article applies to:

The article contains REGISTRY entries for Mouse and Keyboard Drivers. There is a second half of this topic, found in the article Device Driver Entries, Part 3.

These subgroups are included:

There are 5 parts to the Device Driver Entries article series:

Part 1: Device Driver Entries, containing:

Part 2: Mouse and Keyboard Entries

Part 3: Mouse and Keyboard Entries, cont'd, containing:

Part 4: SCSI Miniport Entries

Part 5: Sound Card and Video Device Driver Entries

NOTE: You can view current settings for these device drivers by choosing the Devices button in WinMSD.

Mouse and Keyboard Driver Entries

Parameters in this section are for the mouse and keyboard class and port drivers, including these drivers: 

Busmouse          Inport          Mouclass
i8042             Kbdclass        Sermouse

Microsoft Bus Mouse Port Driver Entries

The following value entries for the Microsoft bus mouse are found in this subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Busmouse\Parameters 

MouseDataQueueSize     REG_DWORD     >= 0x1
Specifies the number of mouse events to be buffered internally by the driver, in nonpaged pool. The allocated size, in bytes, of the internal buffer is this value times the size of the MOUSE_INPUT_DATA structure (defined in NTDDMOU.H). Consider increasing the size if the System log in Event Viewer frequently contains this message from the Busmouse source: "The ring buffer that stores incoming mouse data has overflowed (buffer size is configurable via the Registry)." Default: 0x64 (100) 

NumberOfButtons     REG_DWORD     >= 0x1
Specifies the number of buttons on the bus mouse. If the number of buttons detected at startup time and placed in the Registry is incorrect, this value can be used to override it. Default: 0x2 (two buttons) 

PointerDeviceBaseName     REG_SZ     Base port device name
Specifies the base name for the device object(s) created by the bus mouse port device driver. The device driver also writes information about the device objects into HKEY_LOCAL_MACHINE\HARDWARE\DeviceMap so that the pointer class driver can locate the pointer port device objects. Default: PointerPort

Intel 8042 Port Driver Entries

The i8042prt driver handles the keyboard and mouse port mouse (also known as a PS/2-compatible mouse) for the Intel 8042 controller. These value entries are found in the following subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\i8042prt\Parameters 

KeyboardDataQueueSize     REG_DWORD     >= 0x1
Specifies the number of keyboard events to be buffered internally by the driver, in nonpaged pool. The allocated size, in bytes, of the internal buffer is this value times the size of the KEYBOARD_INPUT_DATA structure (defined in NTDDKBD.H). Consider increasing the size if the System log in Event Viewer contains the following message from the i8042prt source: "The ring buffer that stores incoming keyboard data has overflowed (buffer size is configurable via the Registry)." Default: 0x64 (100) 

KeyboardDeviceBaseName     REG_SZ     Base keyboard port device name
Specifies the base name for the keyboard device object(s) created by the i8042prt device driver. The device driver also writes information about the device objects into HKEY_LOCAL_MACHINE\HARDWARE\DeviceMap so that the keyboard class driver can locate the keyboard port device objects. Default: KeyboardPort 

MouseDataQueueSize     REG_DWORD     >= 0x1
Specifies the number of mouse events to be buffered internally by the driver, in nonpaged pool. Consider increasing the size if the System log in Event Viewer contains the following message from the i8042prt source: "The ring buffer that stores incoming mouse data has overflowed (buffer size is configurable via the Registry)." Default: 0x64 (100) 

MouseResolution     REG_DWORD     Mouse resolution specifier
Used in specifying the mouse port mouse resolution, where 2 to the power of MouseResolution specifies counts-per-millimeter. Default: 0x3 

MouseSynchIn100ns      REG_DWORD     Time, in 100 nanosecond units
Specifies the length of time after which the next mouse interrupt is assumed to indicate the start of a new mouse packet (partial packets are discarded). This enables the driver to synchronize its internal notion of the mouse packet state with the hardware state when a mouse interrupt is lost. Consider modifying this value if the system behaves as if there are random mouse events occurring (for example, button clicks when no mouse button has been pressed). Default: 20,000,000 (2 seconds) 

NumberOfButtons     REG_DWORD     >= 0x1
Specifies the number of buttons on the mouse port mouse. If an incorrect number of buttons is detected at startup time and placed in the Registry, this value can be used to override it. Default: 0x2 

PointerDeviceBaseName     REG_SZ     Base mouse port device name
Specifies the base name for the pointer device object(s) created by the mouse port mouse driver. The device driver also writes information about the device object into HKEY_LOCAL_MACHINE\HARDWARE\DeviceMap so that the pointer class driver can locate the pointer port device objects. Default: PointerPort 

PollStatusIterations     REG_DWORD     Number
Specifies the maximum number of times to check the i8042 controller status register for interrupt verification before dismissing the interrupt as spurious. This value can be used to work around a problem experienced on some hardware (including the Olivetti MIPS computers) where the keyboard interrupt is raised before the Output Buffer Full bit is set in the i8042 status register.

Increase this value if the system seems to suddenly stop taking keyboard interrupts. This can happen if a keyboard interrupt is mistakenly dismissed as spurious, when instead it just took too long to set Output Buffer Full after raising the interrupt. Increasing the value of PollStatusIterations results in a longer execution time for the Interrupt Service Routine if the keyboard interrupt truly is spurious (there is a 1 microsecond delay following each check for Output Buffer Full).

To determine whether the driver is taking keyboard interrupts, press the NUMLOCK key. If the NumLock light on the keyboard turns on or off, this indicates that the i8042prt driver handled the keyboard interrupt correctly. Default: 1 

OverrideKeyboardType     REG_DWORD     >= 0x0
This entry is not usually present. When present, it specifies the keyboard type (overriding the keyboard type detected during system initialization). Add this value entry if the detected keyboard type is incorrect in the Registry. Type values 0x2 and 0x4 indicate an enhanced 101-key or 102-key keyboard, or compatible; other values typically indicate an old-style AT keyboard (83, 84, or 86 keys), or compatible. Default: 0x4 (Enhanced 101-key or 102-key keyboard) 

OverrideKeyboardSubtype     REG_DWORD     >= 0x0
This entry is not usually present. When present, it specifies the OEM- dependent keyboard subtype (overriding the keyboard subtype detected during system initialization). Default: 0x0 

PollingIterations     REG_DWORD     >= 0x400
Specifies the standard number of times to poll the hardware (in polling mode) before giving up and timing out the operation. Consider increasing this value if the driver fails to initialize or work correctly and the System log in Event Viewer contains the following message from the i8042prt source: "The operation on ... timed out (time out is configurable via the Registry)." Default: 0x400 

PollingIterationsMaximum     REG_DWORD     >= 0x400
Specifies the maximum number of times to poll the hardware (in polling mode) before giving up and timing out the operation. This value is used instead of PollingIterations when an old-style AT keyboard is detected (see OverrideKeyboardType). Consider increasing this value if the driver fails to initialize or work correctly and the System log in Event Viewer contains the following message from the i8042prt source: "The operation on ...timed out (time out is configurable via the Registry)." Default: 0x2EE0 

ResendIterations     REG_DWORD     >= 0x1
Specifies the maximum number of times a hardware operation will be retried before timing out. Consider increasing this value if the driver fails to initialize or work correctly and the System log in Event Viewer contains the following message from the i8042prt source: "Exceeded the allowable number of retries (configurable via the Registry) on device ..." Default: 0x3 

SampleRate     REG_DWORD     Mouse sample rate in Hz
Specifies the sample rate for the mouse. Intended for future use. This value might have no effect in the first release of Windows NT. Default: 0x3C (60 Hz)

Microsoft InPort Bus Mouse Port Driver Entries

The value entries for the Microsoft InPort bus mouse are found in this subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Inport\Parameters 

HzMode     REG_DWORD     Mouse sample rate mode specifier
Specifies the value written to the Microsoft InPort mode register to set the mouse sample rate. Might be used in the first release of Windows NT, but should become obsolete. Default: 0x2 (selects 50 Hz) 

MouseDataQueueSize     REG_DWORD     >= 0x1
Specifies the number of mouse events to be buffered internally by the driver, in nonpaged pool. The allocated size, in bytes, of the internal buffer is this value times the size of the MOUSE_INPUT_DATA structure (defined in NTDDMOU.H). Consider increasing the size if the System log in Event Viewer contains the following message from the InPort source: "The ring buffer that stores incoming mouse data has overflowed (buffer size is configurable via the Registry)." Default: 0x64 (100) 

NumberOfButtons     REG_DWORD     >= 0x1
Specifies the number of buttons on the Microsoft InPort bus mouse. If the number of buttons detected at startup time and placed in the Registry is incorrect, this value can be used to override it. Default: 0x2 

PointerDeviceBaseName     REG_SZ     Base port device name
Specifies the base name for the device object(s) created by the Microsoft InPort bus mouse device driver. The device driver also writes information about the device objects into HKEY_LOCAL_MACHINE\HARDWARE\DeviceMap so that the pointer class driver can locate the pointer port device objects. Default: PointerPort 

SampleRate     REG_DWORD     Mouse sample rate in Hz
Specifies the sample rate for the Microsoft InPort bus mouse. Intended for future use. This value might have no effect in the first release of Windows NT. Default: 0x32 (50 Hz)

Reference: "The Windows NT Resource Kit for Operating System Version 3.1".

Additional query words: prodnt 

Keywords          : kbprint ntprint ntregistry NTSrvWkst 
Version           : winnt:3.5,3.51,4.0
Platform          : winnt

Last Reviewed: March 7, 1999