# what is i8042?

## kompressor

I was poking around in /proc/interrupts

and I noticed that what used to be called mouse is now: i8042

it also apears as the keyboard interrupt as well. 

Just curious as what the number means.

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## codergeek42

On mine it seems to be the keyboard port:

```
peter@deep-thought ~ $ cat /proc/interrupts 

           CPU0       

  0:     455112          XT-PIC  timer

  1:       1762          XT-PIC  i8042

  2:          0          XT-PIC  cascade

  7:          1          XT-PIC  parport0

  8:          2          XT-PIC  rtc

  9:          1          XT-PIC  acpi

 10:      23528          XT-PIC  radeon@pci:0000:01:00.0

 11:      26282          XT-PIC  ehci_hcd:usb1, ohci_hcd:usb2, uhci_hcd:usb4, uhci_hcd:usb5

 12:       3884          XT-PIC  yenta, ohci_hcd:usb3, VIA686A, 0.0

 14:      15071          XT-PIC  ide0

 15:       3786          XT-PIC  ide1

NMI:          0 

LOC:          0 

ERR:          0

MIS:          0
```

```

peter@deep-thought ~ $ grep 8042 /var/log/dmesg 

serio: i8042 KBD port at 0x60,0x64 irq 1
```

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## dtor

It is keyboard controller (well, part of SuperIO chip that emulates KBD on motherboards nowadays). It has a keyboard port and 1 or 4 AUX ports. 8042 is the chip name of the original Intel controller (like 8253 timer, 8250 serial port, 8086 CPU, etc.

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