Microsoft KB Archive/102989

= Device Driver Entries, PART 2--Mouse/Keyboard Driver =

Article ID: 102989

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q102989



SUMMARY
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:
 * Microsoft Bus Mouse Port Driver
 * Intel 8042 Port Driver
 * Microsoft InPort Bus Mouse Port Driver

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

Part 1: Device Driver Entries, containing:
 * File System Drivers and Recognizers
 * Disk, Serial and Parallel Ports

Part 2: Mouse and Keyboard Entries

Part 3: Mouse and Keyboard Entries, cont'd, containing:
 * Microsoft Serial Mouse Port Driver
 * Mouse Class Driver
 * Keyboard Class Driver
 * Device Map Entries for the Keyboard and Mouse

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: kbinfo kbprint KB102989

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