#define SCHIZO_PCI_CTRL                (0x2000UL)
 #define SCHIZO_PCICTRL_BUS_UNUS        (1UL << 63UL) /* Safari */
+#define SCHIZO_PCICTRL_DTO_INT (1UL << 61UL) /* Tomatillo */
 #define SCHIZO_PCICTRL_ARB_PRIO (0x1ff << 52UL) /* Tomatillo */
 #define SCHIZO_PCICTRL_ESLCK   (1UL << 51UL) /* Safari */
 #define SCHIZO_PCICTRL_ERRSLOT (7UL << 48UL) /* Safari */
        schizo_write(pbm->pbm_regs + SCHIZO_PCI_IRQ_RETRY,
                     SCHIZO_IRQ_RETRY_INF);
 
-       /* Enable arbiter for all PCI slots.  Also, disable PCI interval
-        * timer so that DTO (Discard TimeOuts) are not reported because
-        * some Schizo revisions report them erroneously.
-        */
        tmp = schizo_read(pbm->pbm_regs + SCHIZO_PCI_CTRL);
-       if (pbm->chip_type == PBM_CHIP_TYPE_SCHIZO_PLUS &&
-           pbm->chip_version == 0x5 &&
-           pbm->chip_revision == 0x1)
-               tmp |= 0x0f;
-       else
-               tmp |= 0xff;
 
-       tmp &= ~SCHIZO_PCICTRL_PTO;
+       /* Enable arbiter for all PCI slots.  */
+       tmp |= 0xff;
+
        if (pbm->chip_type == PBM_CHIP_TYPE_TOMATILLO &&
            pbm->chip_version >= 0x2)
                tmp |= 0x3UL << SCHIZO_PCICTRL_PTO_SHIFT;
-       else
-               tmp |= 0x1UL << SCHIZO_PCICTRL_PTO_SHIFT;
 
        if (!prom_getbool(pbm->prom_node, "no-bus-parking"))
                tmp |= SCHIZO_PCICTRL_PARK;
+       else
+               tmp &= ~SCHIZO_PCICTRL_PARK;
 
        if (pbm->chip_type == PBM_CHIP_TYPE_TOMATILLO &&
            pbm->chip_version <= 0x1)
-               tmp |= (1UL << 61);
+               tmp |= SCHIZO_PCICTRL_DTO_INT;
        else
-               tmp &= ~(1UL << 61);
+               tmp &= ~SCHIZO_PCICTRL_DTO_INT;
 
        if (pbm->chip_type == PBM_CHIP_TYPE_TOMATILLO)
                tmp |= (SCHIZO_PCICTRL_MRM_PREF |