Fix Apple keyboard Caps Lock delay.

README.md

Fix Apple keyboard Caps Lock delay.

Useful when remapped to another key.

Compile the code:

    gcc apple-kb-caps.c -o apple-kb-caps

Move the executable apple-kb-caps and script run-apple-kb-caps to ~/bin/.

Run the script (require sudo password):

    run-apple-kb-caps 

Credit: jmrk

apple-kb-caps.c

#include <linux/hidraw.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char **argv) {
  if (argc != 2 || strcmp(argv[1], "-h") == 0) {
    printf("Pass a hidraw device as the first and only parameter!\n");
    printf("You may find the right device with:\n");
    printf(" dmesg | grep apple | grep Keyboard | grep input0 | tail -1 | "
           "sed -e 's/.*hidraw\\([[:digit:]]\\+\\).*/\\/dev\\/hidraw\\1/'\n");
    printf("For example: /dev/hidraw1\n");
    return 1;
  }
  int fd, i, res, desc_size = 0;
  char buf[256];
  struct hidraw_devinfo info;
  char *device = argv[1];
  fd = open(device, O_RDWR | O_NONBLOCK);
  if (fd < 0) {
    perror("Unable to open device");
    return 1;
  }
  memset(&info, 0, sizeof(info));
  memset(buf, 0, sizeof(buf));

  // Get Report Descriptor Size
  res = ioctl(fd, HIDIOCGRDESCSIZE, &desc_size);
  if (res < 0)
    perror("HIDIOCGRDESCSIZE");

  if (desc_size != 75) {
    printf("Error: unexpected descriptor size %d; you've probably got "
           "the wrong hidraw device!\n", desc_size);
    return 1;
  }

  // Get Raw Info
  res = ioctl(fd, HIDIOCGRAWINFO, &info);
  if (res < 0) {
    perror("HIDIOCGRAWINFO");
  } else {
    if (info.vendor != 0x05ac) {
      printf("Error: Wrong vendor ID, make sure you got the right "
             "hidraw device!\n");
      return 1;
    }
    if (info.product != 0x0251) {
      printf("Warning: Unknown product ID 0x%x!\n", info.product);
    }
  }

  // Get Feature
  buf[0] = 0x09; // Report Number
  res = ioctl(fd, HIDIOCGFEATURE(256), buf);
  if (res < 0) {
    perror("HIDIOCGFEATURE");
  } else {
    printf("HID Feature Report (before change):\n\t");
    for (i = 0; i < res; i++) printf("%hhx ", buf[i]);
    puts("\n");
  }

  // Set Feature
  buf[0] = 0x09; // Report Number
  buf[1] = 0x00; // Report data
  buf[2] = 0x00; // padding
  buf[3] = 0x00; // padding
  res = ioctl(fd, HIDIOCSFEATURE(4), buf);
  if (res < 0)
    perror("HIDIOCSFEATURE");
  else
    printf("Caps lock delay disabled.\n");

  // Get Feature
  buf[0] = 0x09; // Report Number
  res = ioctl(fd, HIDIOCGFEATURE(256), buf);
  if (res < 0) {
    perror("HIDIOCGFEATURE");
  } else {
    printf("HID Feature Report (after change):\n\t");
    for (i = 0; i < res; i++) printf("%hhx ", buf[i]);
    puts("\n");
  }

  close(fd);
  return 0;
}

run-apple-kb-caps

#!/bin/bash

# Disable Apple Keyboard Caps Lock Key Delay
# apple-kb-caps /dev/hidraw1
sudo ~/bin/apple-kb-caps `dmesg | grep apple | grep Keyboard | grep input0 | tail -1 | sed -e 's/.*hidraw\([[:digit:]]\+\).*/\/dev\/hidraw\1/'`