request_irq fails to get interrupt 12

[Alan Bennett]

Freescale experts.  Why on earth can't I request the IRQ for Timer1?

static int __init
dvr_ph_init(void)
{
	u32	rv;
	int k;
	//rv = driver_register(&dvr_ph_driver);
	for (k=0;k<64;k++) {
		rv = request_irq(k,dvrph_isr , 0, "dvr_ph", NULL);
		if (rv!=-38) printkplus("request_irq for %d returns %d", k,rv);
	}
	return rv;
}

Results in:
dvr_ph_init    145 - enter the routine
dvr_ph_init    155 -
dvr_ph_init    161 - request_irq for 16 returns -16  (vector 16 = TMCNT)
dvr_ph_init    161 - request_irq for 32 returns 0  (vector 32 = FCC1)
dvr_ph_init    161 - request_irq for 33 returns -16  (vector 33 = FCC2)
dvr_ph_init    161 - request_irq for 40 returns 0  (vector 40 = SCC1)
dvr_ph_init    161 - request_irq for 43 returns 0  (vector 43 = SCC4)