From Mikael Petterson:


  Booting kernel 2.5.74 on a PowerMac with CONFIG_BLK_DEV_IDE_PMAC=y
  results in an oops during IDE init, and the box then reboots.

  The patch below updates drivers/ide/ppc/pmac.c to also set up the
  hwif->ide_dma_queued_off and hwif->ide_dma_queued_on function
  pointers, which fixes the oops. Tested on my ancient PM4400.