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man pages section 4: Device and Network Interfaces

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Updated: Thursday, June 13, 2019
 
 

virtualkm(4D)

Name

virtualkm - Virtual keyboard and mouse

Synopsis

/dev/kbd
/dev/mouse
#include <sys/types.h>
#include <sys/kbio.h>
int ioctl(int fildes, int command, ... /*arg*/);

Description

A virtual keyboard or mouse is an abstraction of one or more physical keyboards or mice (USB or PS2) connected to a system. Input streams for these physical devices are coalesced into a single input stream and appear as a single device to the upper layers.

/dev/kbd is the virtual keyboard device file. Inputs from multiple keyboards are coalesced into a single input stream, meaning that all keyboards appear as a single keyboard to a console or window system and accordingly, are treated as a single device. The virtual keyboard layout is consistent with the layout of the first keyboard plugged into the system. Note that on x86 platforms, the virtual keyboard layout can be overloaded by eeprom(8).

/dev/mouse is the virtual mouse device file. Inputs from multiple mice are coalesced into a single input stream, meaning that all mice appear as single mouse to the window system.

Commands from applications are dispatched by the virtual keyboard/mouse facility to the underlying physical devices and will succeed provided that one of the underlying devices responds with success. For example, a single command issued to turn on LED's will turn on corresponding LED's for all underlying physical keyboards.

Although physical keyboards/mice are linked to the virtual keyboard/mouse facility, each may be opened separately by accessing its associated device file. (For example, /dev/usb/hid0 for a usb mouse). Directly accessing a device file can be useful for multi-seat, accessibility helpers, or similar purposes.

When a single physical device is opened via its associated device file, it is automatically removed from the single virtual input stream. When closed, it is automatically re– coalesced into the single virtual input stream.

Under the virtualkm facility, the PS/2 mouse is coalesced into a virtual mouse single input stream and can be accessed using the /dev/mouse file. (Note that in previous releases, the PS/2 mouse was accessed via the /dev/kdmouse physical device file). In the current release, you use the /dev/kdmouse file to directly access the physical PS/2 mouse.

INTERFACES

The virtual mouse provides the following event ID's for mouse capability changes:

MOUSE_CAP_CHANGE_NUM_BUT

This event is reported when the total number of mouse buttons changes. The Firm_event.value is set to the new button total, which is the maximum number of all mice buttons. Other fields are ignored.

MOUSE_CAP_CHANGE_NUM_WHEEL

This event is reported when the total number of mouse wheels changes. The Firm_event.value is set to the new wheel total. Other fields are ignored. The event value (Firm_event.value) can be 0 (no wheel), 1 (vertical wheel), or 2 (vertical and horizontal wheel).

The Firm_event structure is described in <sys/vuid_event.h>. As with other events, firm events are received using read(2).

Event ID's are used by applications (including certain mouse demo applications) that are programmed to graphically represent the actual number of buttons and wheels on a mouse. When an application of this type receives a Firm_event with a ID MOUSE_CAP_CHANGE_NUM_BUT or MOUSE_CAP_CHANGE_NUM_WHEEL event, it is instructed to update its state information using the new value. Consider, for example, a mouse demo application whose sole function is to display a mouse with buttons that graphically correspond to the actual number of buttons on the mouse. If, for example, the system has a single two-button USB mouse attached, the application, by default, will graphically display the mouse with a left and a right button. However, if a another three-button USB mouse is hot-plugged into the system, a MOUSE_CAP_CHANGE_NUM_BUT Firm event with Firm_event.value of three instructs the demo application to update the mouse display to indicate three buttons.

Ioctls

KIOCSETFREQ

Sets the frequency for either keyboard beeper or console beeper. To set the corresponding beeper frequency, arg must point to a freq_request structure:


struct freq_request {                              
        enum fr_beep_type type; /* beep type */    
        int16_t freq;           /* frequency */    
};

Where type is the corresponding beeper type defined as:

enum fr_beep_type { CONSOLE_BEEP =1, KBD_BEEP =2 };

and freq is the frequency value to be set as the beeper frequency indicated by type. This value should be between 0 and 32767 with border inclusive.

Files

/dev/kbd

Virtual Keyboard device file.

/dev/mouse

Virtual Mouse device file.

/dev/kdmouse

Physical PS/2 mouse device file.

/dev/usb/hid*

Physical USB keyboard/mouse device file.

/etc/dacf.conf

Device auto-configuration file.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Architecture
SPARC, x86
Availability
system/kernel, system/kernel/platform, driver/usb, driver/i86pc/platform, system/kernel/platform
Interface Stability
Committed

See Also

kbd(1), read(2), hid(4D), usba(4D), kb(4M), usbkbm(4M), usbms(4M), vuidmice(4M), attributes(7), eeprom(8)

Diagnostics

The messages described below may appear on the system console as well as being logged. All messages are formatted in the following manner:

WARNING: Error message...
conskbd: keyboard is not available for system debugging: device_path.

Errors were encountered while entering kmdb during initialization for debugger mode. As a result, the keyboard is not available.

conskbd: keyboard is not available: <device_path>

Errors were encountered while exiting kmdb during un-initialization for debugger mode. As a result, the keyboard is not available.

Failed to relink the mouse <device_path> underneath virtual mouse

An error was encountered and the mouse is unavailable. (When a mouse is physically opened via a physical device file such as /dev/usb/hid0, it is removed from the single virtual input stream (/dev/mouse). When closed, it is re-coalesced into a single virtual input stream beneath /dev/mouse. If an error is encountered, (for example, the mouse has been physically removed), it is unavailable beneath /dev/mouse.

Notes

Currently, the virtualkm device supports only USB and PS2 keyboards and mice.