iSight

The iSight in the MacBook has to be initialised with firmware.

For reference, in the AppleUSBVideoSupport binaries, the firmware starts at

The firmware blob is structured like this:

__be16 data_length;
__be16 value;
__u8   data[data_length];

This type of record repeats until data_length is 0x8001, which means you've reached the end.

Now, to initialise the device with this firmware, do the following (I'm writing it in terms of libusb's usb_control_msg):

1. usb_control_msg(dev, 0x40, 0xA0, 0xe600, 0, "1", 1, ...)
2. for each firmware record, traverse the data as follows:
   1. initialise value to the record's value variable
   2. split the data up into 50 byte pieces (the last one may be shorter) and upload each piece using usb_control_msg(dev, 0x40, 0xA0, value, 0, chunk, chunklen, ...), increasing the value variable by 50 after each chunk. chunklen is obviously 50 for all but (possibly) the last block
3. finish off with usb_control_msg(dev, 0x40, 0xA0, 0xe600, 0, "0", 1, ...)

If any of the calls fail, that's an error.

At this point, the device disconnects from and reconnects to the USB bus.

Ronald Bultje has written code to load the firmware.