Here is one segment code for Linux drivers.
I know it is used to control CD-ROM to play music.
However, I don't understand it completely casue
I seldom touch the interface between software and
hardware.
The codes are:
2532 case CDROMPLAYMSF: {
2533 struct cdrom_msf msf;
2534 if (!CDROM_CAN(CDC_PLAY_AUDIO))
2535 return -ENOSYS;
2536 cdinfo(CD_DO_IOCTL, "entering CDROMPLAYMSF\n");
2537 IOCTL_IN(arg, struct cdrom_msf, msf);
2538 return cdo->audio_ioctl(cdi, cmd, &msf);
2539 }

My problem is :
1) It this the lowest code to interact with hardware?
2) Is this the final realization of system call ioctl?
3) What's the concrete cdo->audio_ioctl? I am not sure which function
it is in kernel.


Thanks a lot.
I am really new to this.


---cdyang