DVD_AUTH ioctl fails with aic7xxx / 2.4.4

[Jason Lunz <j@falooley.org>]

I've set up a Pioneer 305S scsi dvd-rom on an old adaptec card using the
stock aic7xxx driver included with the 2.4.4 kernel (not the old_aic7xxx
one). Everything works well, except when trying to access an encrypted
file on a DVD. This ioctl from libcss fails:

static int _get_title_key(int fd, int agid, int lba, char *key, char *key_title)
{
	dvd_authinfo ai;
	int i;

	ai.type = DVD_LU_SEND_TITLE_KEY;

	ai.lstk.agid = agid;
	ai.lstk.lba = lba;

	if (ioctl (fd, DVD_AUTH, &ai)) {
		perror ("GetTitleKey failed");
		return -1;
	}

All I see from the kernel is:

	sr1: CDROM (ioctl) reports ILLEGAL REQUEST.

This happens with any DVD. Can someone tell me what the problem is? I
seem to be using the same libcss that everyone else uses with no
problem, and everything is properly configured, AFAIK.

thanks,

Jason