Provides access to the natively attached keyboard.
The kbd special file is the interface to the native keyboard. It provides an interface through which applications can receive operator input from the keyboard, control the keyboard LED's, and changing various keyboard parameters. The special file also allows an application to send an audible signal to the operator via the speaker located within the keyboard.
The sound volume, click volume, typematic rate and typematic delay are configurable by the application through the ioctl subroutine. These changes are not reflected in the ODM database. To change these attributes in the ODM database, use the chhwkbd command.
open
This subroutine call creates a channel between the application and the natively attached keyboard. Two channels are supported. The open subroutine call is processed normally except that the MODE and Oflag parameters are ignored. All keyboard input is flushed until an input ring is established. Only the input ring associated with the most recent open receives input reports.
close
When the kbd device has been opened twice, input is reported through the input ring registered previous to the first open, after the close subroutine call.
read and write
The keyboard device driver does not return nor accept data via read and write. These calls behave as if the call was made to /dev/null. Input data is received from the input drivers via the input ring.
ioctl
The keyboard device driver supports the following ioctl commands:
| Item | Description |
|---|---|
| IOCINFO | Return devinfo structure. |
| KSALARM | Sound alarm. |
| KSCFGCLICK | Control keyboard click. |
| KSDIAGMODE | Enable/disable diagnostics mode (user mode only). |
| KSLED | Set/reset keyboard LED's. |
| KSKAP | Enable/disable keep alive poll (user mode only). |
| KSKAPACK | Acknowledge keep alive poll (user mode only). |
| KSQUERYID | Query keyboard device identifier. |
| KSQUERYSV | Query keyboard service vector (kernel mode only). |
| KSREGRING | Register input ring. |
| KSRFLUSH | Flush input ring. |
| KSTDELAY | Set typamatic delay. |
| KSTRATE | Set typamatic rate. |
| KSVOLUME | Set alarm volume |
The error codes can be found in the /usr/include/sys/errno.h file.
| Item | Description |
|---|---|
| EFAULT | indicates insufficient authority to access address or invalid address. |
| EIO | indicates that an I/O error occurred. |
| ENOMEM | indicates there was insufficient memory for required paging operation. |
| ENOSPC | indicates there was insufficient file system or paging space. |
| EINVAL | indicates that an invalid argument was specified. |
| EINTR | indicates the request was interrupted by signal. |
| EPERM | indicates that a permanent error occurred. |
| EBUSY | indicates the device is busy. |
| ENXIO | indicates unsupported device number was specified. |
| ENODEV | indicates an unsupported device or device type mismatch. |
| Item | Description |
|---|---|
| /usr/include/sys/inputdd.h | Contains declarations for ioctl commands and input ring report format. |