diff --git a/Makefile.target b/Makefile.target
index 690f30b..415046b 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -265,7 +265,7 @@ obj-arm-y += arm-semi.o
 obj-arm-y += pxa2xx.o pxa2xx_pic.o pxa2xx_gpio.o pxa2xx_timer.o pxa2xx_dma.o
 obj-arm-y += pxa2xx_lcd.o pxa2xx_mmci.o pxa2xx_pcmcia.o pxa2xx_keypad.o
 obj-arm-y += pflash_cfi01.o gumstix.o
-obj-arm-y += zaurus.o ide.o serial.o spitz.o tosa.o tc6393xb.o
+obj-arm-y += zaurus.o ide.o isa-bus.o serial.o spitz.o tosa.o tc6393xb.o
 obj-arm-y += omap1.o omap_lcdc.o omap_dma.o omap_clk.o omap_mmc.o omap_i2c.o
 obj-arm-y += omap2.o omap_dss.o soc_dma.o
 obj-arm-y += omap_sx1.o palm.o tsc210x.o
@@ -279,7 +279,7 @@ obj-arm-y += syborg_virtio.o
 
 obj-sh4-y = shix.o r2d.o sh7750.o sh7750_regnames.o tc58128.o
 obj-sh4-y += sh_timer.o sh_serial.o sh_intc.o sh_pci.o sm501.o serial.o
-obj-sh4-y += ide.o
+obj-sh4-y += ide.o isa-bus.o
 
 obj-m68k-y = an5206.o mcf5206.o mcf_uart.o mcf_intc.o mcf5208.o mcf_fec.o
 obj-m68k-y += m68k-semi.o dummy_m68k.o
diff --git a/hw/cs4231a.c b/hw/cs4231a.c
index 5516867..d482e04 100644
--- a/hw/cs4231a.c
+++ b/hw/cs4231a.c
@@ -60,10 +60,9 @@ static struct {
 
 typedef struct CSState {
     QEMUSoundCard card;
-    qemu_irq *pic;
+    qemu_irq pic;
     uint32_t regs[CS_REGS];
     uint8_t dregs[CS_DREGS];
-    int irq;
     int dma;
     int port;
     int shift;
@@ -483,7 +482,7 @@ IO_WRITE_PROTO (cs_write)
         case Alternate_Feature_Status:
             if ((s->dregs[iaddr] & PI) && !(val & PI)) {
                 /* XXX: TI CI */
-                qemu_irq_lower (s->pic[s->irq]);
+                qemu_irq_lower (s->pic);
                 s->regs[Status] &= ~INT;
             }
             s->dregs[iaddr] = val;
@@ -503,7 +502,7 @@ IO_WRITE_PROTO (cs_write)
 
     case Status:
         if (s->regs[Status] & INT) {
-            qemu_irq_lower (s->pic[s->irq]);
+            qemu_irq_lower (s->pic);
         }
         s->regs[Status] &= ~INT;
         s->dregs[Alternate_Feature_Status] &= ~(PI | CI | TI);
@@ -588,7 +587,7 @@ static int cs_dma_read (void *opaque, int nchan, int dma_pos, int dma_len)
         s->regs[Status] |= INT;
         s->dregs[Alternate_Feature_Status] |= PI;
         s->transferred = 0;
-        qemu_irq_raise (s->pic[s->irq]);
+        qemu_irq_raise (s->pic);
     }
     else {
         s->transferred += written;
@@ -643,8 +642,7 @@ int cs4231a_init (qemu_irq *pic)
 
     s = qemu_mallocz (sizeof (*s));
 
-    s->pic = pic;
-    s->irq = conf.irq;
+    s->pic = isa_reserve_irq(conf.irq);
     s->dma = conf.dma;
     s->port = conf.port;
 
diff --git a/hw/ide.c b/hw/ide.c
index 0bde632..28b93f4 100644
--- a/hw/ide.c
+++ b/hw/ide.c
@@ -3610,8 +3610,8 @@ void pci_piix3_ide_init(PCIBus *bus, BlockDriverState **hd_table, int devfn,
     pci_register_bar((PCIDevice *)d, 4, 0x10,
                            PCI_ADDRESS_SPACE_IO, bmdma_map);
 
-    ide_init2(&d->ide_if[0], hd_table[0], hd_table[1], pic[14]);
-    ide_init2(&d->ide_if[2], hd_table[2], hd_table[3], pic[15]);
+    ide_init2(&d->ide_if[0], hd_table[0], hd_table[1], isa_reserve_irq(14));
+    ide_init2(&d->ide_if[2], hd_table[2], hd_table[3], isa_reserve_irq(15));
     ide_init_ioport(&d->ide_if[0], 0x1f0, 0x3f6);
     ide_init_ioport(&d->ide_if[2], 0x170, 0x376);
 
@@ -3650,6 +3650,9 @@ void pci_piix4_ide_init(PCIBus *bus, BlockDriverState **hd_table, int devfn,
     pci_register_bar((PCIDevice *)d, 4, 0x10,
                            PCI_ADDRESS_SPACE_IO, bmdma_map);
 
+    /*
+     * These should call isa_reserve_irq() instead when MIPS supports it
+     */
     ide_init2(&d->ide_if[0], hd_table[0], hd_table[1], pic[14]);
     ide_init2(&d->ide_if[2], hd_table[2], hd_table[3], pic[15]);
     ide_init_ioport(&d->ide_if[0], 0x1f0, 0x3f6);
diff --git a/hw/isa-bus.c b/hw/isa-bus.c
index f8ba7c0..4ac4fad 100644
--- a/hw/isa-bus.c
+++ b/hw/isa-bus.c
@@ -76,6 +76,27 @@ void isa_connect_irq(ISADevice *dev, int devnr, int isairq)
     }
 }
 
+/*
+ * isa_reserve_irq() reserves the ISA irq and returns the corresponding
+ * qemu_irq entry for the i8259.
+ *
+ * This function is only for special cases such as the 'ferr', and
+ * temporary use for normal devices until they are converted to qdev.
+ */
+qemu_irq isa_reserve_irq(int isairq)
+{
+    if (isairq < 0 || isairq > 15) {
+        fprintf(stderr, "isa irq %d invalid\n", isairq);
+        exit(1);
+    }
+    if (isabus->assigned & (1 << isairq)) {
+        fprintf(stderr, "isa irq %d already assigned\n", isairq);
+        exit(1);
+    }
+    isabus->assigned |= (1 << isairq);
+    return isabus->irqs[isairq];
+}
+
 void isa_init_irq(ISADevice *dev, qemu_irq *p)
 {
     assert(dev->nirqs < ARRAY_SIZE(dev->irqs));
diff --git a/hw/isa.h b/hw/isa.h
index 1a3bb5b..31853a0 100644
--- a/hw/isa.h
+++ b/hw/isa.h
@@ -27,6 +27,7 @@ struct ISADeviceInfo {
 ISABus *isa_bus_new(DeviceState *dev);
 void isa_bus_irqs(qemu_irq *irqs);
 void isa_connect_irq(ISADevice *dev, int devirq, int isairq);
+qemu_irq isa_reserve_irq(int isairq);
 void isa_init_irq(ISADevice *dev, qemu_irq *p);
 void isa_qdev_register(ISADeviceInfo *info);
 ISADevice *isa_create_simple(const char *name, uint32_t iobase, uint32_t iobase2);
diff --git a/hw/pc.c b/hw/pc.c
index abb7356..fc6a925 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1043,13 +1043,14 @@ static void audio_init (PCIBus *pci_bus, qemu_irq *pic)
 }
 #endif
 
-static void pc_init_ne2k_isa(NICInfo *nd, qemu_irq *pic)
+static void pc_init_ne2k_isa(NICInfo *nd)
 {
     static int nb_ne2k = 0;
 
     if (nb_ne2k == NE2000_NB_MAX)
         return;
-    isa_ne2000_init(ne2000_io[nb_ne2k], pic[ne2000_irq[nb_ne2k]], nd);
+    isa_ne2000_init(ne2000_io[nb_ne2k],
+                    isa_reserve_irq(ne2000_irq[nb_ne2k]), nd);
     nb_ne2k++;
 }
 
@@ -1276,7 +1277,6 @@ static void pc_init1(ram_addr_t ram_size,
     isa_irq_state = qemu_mallocz(sizeof(*isa_irq_state));
     isa_irq_state->i8259 = i8259;
     isa_irq = qemu_allocate_irqs(isa_irq_handler, isa_irq_state, 24);
-    ferr_irq = isa_irq[13];
 
     if (pci_enabled) {
         pci_bus = i440fx_init(&i440fx_state, isa_irq);
@@ -1286,6 +1286,7 @@ static void pc_init1(ram_addr_t ram_size,
         isa_bus_new(NULL);
     }
     isa_bus_irqs(isa_irq);
+    ferr_irq = isa_reserve_irq(13);
 
     /* init basic PC hardware */
     register_ioport_write(0x80, 1, 1, ioport80_write, NULL);
@@ -1311,7 +1312,7 @@ static void pc_init1(ram_addr_t ram_size,
         }
     }
 
-    rtc_state = rtc_init(0x70, isa_irq[8], 2000);
+    rtc_state = rtc_init(0x70, isa_reserve_irq(8), 2000);
 
     qemu_register_boot_set(pc_boot_set, rtc_state);
 
@@ -1321,7 +1322,7 @@ static void pc_init1(ram_addr_t ram_size,
     if (pci_enabled) {
         isa_irq_state->ioapic = ioapic_init();
     }
-    pit = pit_init(0x40, isa_irq[0]);
+    pit = pit_init(0x40, isa_reserve_irq(0));
     pcspk_init(pit);
     if (!no_hpet) {
         hpet_init(isa_irq);
@@ -1329,14 +1330,14 @@ static void pc_init1(ram_addr_t ram_size,
 
     for(i = 0; i < MAX_SERIAL_PORTS; i++) {
         if (serial_hds[i]) {
-            serial_init(serial_io[i], isa_irq[serial_irq[i]], 115200,
+            serial_init(serial_io[i], isa_reserve_irq(serial_irq[i]), 115200,
                         serial_hds[i]);
         }
     }
 
     for(i = 0; i < MAX_PARALLEL_PORTS; i++) {
         if (parallel_hds[i]) {
-            parallel_init(parallel_io[i], isa_irq[parallel_irq[i]],
+            parallel_init(parallel_io[i], isa_reserve_irq(parallel_irq[i]),
                           parallel_hds[i]);
         }
     }
@@ -1347,7 +1348,7 @@ static void pc_init1(ram_addr_t ram_size,
         NICInfo *nd = &nd_table[i];
 
         if (!pci_enabled || (nd->model && strcmp(nd->model, "ne2k_isa") == 0))
-            pc_init_ne2k_isa(nd, isa_irq);
+            pc_init_ne2k_isa(nd);
         else
             pci_nic_init(nd, "e1000", NULL);
     }
@@ -1368,7 +1369,8 @@ static void pc_init1(ram_addr_t ram_size,
         pci_piix3_ide_init(pci_bus, hd, piix3_devfn + 1, isa_irq);
     } else {
         for(i = 0; i < MAX_IDE_BUS; i++) {
-            isa_ide_init(ide_iobase[i], ide_iobase2[i], isa_irq[ide_irq[i]],
+            isa_ide_init(ide_iobase[i], ide_iobase2[i],
+                         isa_reserve_irq(ide_irq[i]),
 	                 hd[MAX_IDE_DEVS * i], hd[MAX_IDE_DEVS * i + 1]);
         }
     }
@@ -1398,7 +1400,8 @@ static void pc_init1(ram_addr_t ram_size,
         i2c_bus *smbus;
 
         /* TODO: Populate SPD eeprom data.  */
-        smbus = piix4_pm_init(pci_bus, piix3_devfn + 3, 0xb100, isa_irq[9]);
+        smbus = piix4_pm_init(pci_bus, piix3_devfn + 3, 0xb100,
+                              isa_reserve_irq(9));
         for (i = 0; i < 8; i++) {
             DeviceState *eeprom;
             eeprom = qdev_create((BusState *)smbus, "smbus-eeprom");
diff --git a/hw/sb16.c b/hw/sb16.c
index 2506d98..9f7680d 100644
--- a/hw/sb16.c
+++ b/hw/sb16.c
@@ -56,7 +56,7 @@ static struct {
 
 typedef struct SB16State {
     QEMUSoundCard card;
-    qemu_irq *pic;
+    qemu_irq pic;
     int irq;
     int dma;
     int hdma;
@@ -190,7 +190,7 @@ static void aux_timer (void *opaque)
 {
     SB16State *s = opaque;
     s->can_write = 1;
-    qemu_irq_raise (s->pic[s->irq]);
+    qemu_irq_raise (s->pic);
 }
 
 #define DMA8_AUTO 1
@@ -598,7 +598,7 @@ static void command (SB16State *s, uint8_t cmd)
         case 0xf3:
             dsp_out_data (s, 0xaa);
             s->mixer_regs[0x82] |= (cmd == 0xf2) ? 1 : 2;
-            qemu_irq_raise (s->pic[s->irq]);
+            qemu_irq_raise (s->pic);
             break;
 
         case 0xf9:
@@ -766,7 +766,7 @@ static void complete (SB16State *s)
                 bytes = samples << s->fmt_stereo << (s->fmt_bits == 16);
                 ticks = (bytes * ticks_per_sec) / freq;
                 if (ticks < ticks_per_sec / 1024) {
-                    qemu_irq_raise (s->pic[s->irq]);
+                    qemu_irq_raise (s->pic);
                 }
                 else {
                     if (s->aux_ts) {
@@ -858,10 +858,10 @@ static void legacy_reset (SB16State *s)
 
 static void reset (SB16State *s)
 {
-    qemu_irq_lower (s->pic[s->irq]);
+    qemu_irq_lower (s->pic);
     if (s->dma_auto) {
-        qemu_irq_raise (s->pic[s->irq]);
-        qemu_irq_lower (s->pic[s->irq]);
+        qemu_irq_raise (s->pic);
+        qemu_irq_lower (s->pic);
     }
 
     s->mixer_regs[0x82] = 0;
@@ -897,7 +897,7 @@ static IO_WRITE_PROTO (dsp_write)
             if (s->v2x6 == 1) {
                 if (0 && s->highspeed) {
                     s->highspeed = 0;
-                    qemu_irq_lower (s->pic[s->irq]);
+                    qemu_irq_lower (s->pic);
                     control (s, 0);
                 }
                 else {
@@ -1008,7 +1008,7 @@ static IO_READ_PROTO (dsp_read)
         if (s->mixer_regs[0x82] & 1) {
             ack = 1;
             s->mixer_regs[0x82] &= 1;
-            qemu_irq_lower (s->pic[s->irq]);
+            qemu_irq_lower (s->pic);
         }
         break;
 
@@ -1017,7 +1017,7 @@ static IO_READ_PROTO (dsp_read)
         if (s->mixer_regs[0x82] & 2) {
             ack = 1;
             s->mixer_regs[0x82] &= 2;
-            qemu_irq_lower (s->pic[s->irq]);
+            qemu_irq_lower (s->pic);
         }
         break;
 
@@ -1231,7 +1231,7 @@ static int SB_read_DMA (void *opaque, int nchan, int dma_pos, int dma_len)
 
     if (s->left_till_irq <= 0) {
         s->mixer_regs[0x82] |= (nchan & 4) ? 2 : 1;
-        qemu_irq_raise (s->pic[s->irq]);
+        qemu_irq_raise (s->pic);
         if (0 == s->dma_auto) {
             control (s, 0);
             speaker (s, 0);
@@ -1408,8 +1408,7 @@ int SB16_init (qemu_irq *pic)
     s = qemu_mallocz (sizeof (*s));
 
     s->cmd = -1;
-    s->pic = pic;
-    s->irq = conf.irq;
+    s->pic = isa_reserve_irq(conf.irq);
     s->dma = conf.dma;
     s->hdma = conf.hdma;
     s->port = conf.port;
