diff --git a/src/chipset/intel_piix.c b/src/chipset/intel_piix.c
index d67eeb0471..89f82d9a5a 100644
--- a/src/chipset/intel_piix.c
+++ b/src/chipset/intel_piix.c
@@ -1535,6 +1535,19 @@ piix_speed_changed(void *priv)
         timer_on_auto(&dev->fast_off_timer, ((double) cpu_fast_off_val + 1) * dev->fast_off_period);
 }
 
+static void
+piix_smsc_usb_smi_raise(void* priv)
+{
+    piix_t *dev = (piix_t *) priv;
+    if (!dev)
+        return;
+
+    if ((dev->acpi->regs.glben & 1)) {
+        dev->acpi->regs.glbsts |= 2;
+        acpi_raise_smi(dev->acpi, 1);
+    }
+}
+
 static void *
 piix_init(const device_t *info)
 {
@@ -1554,6 +1567,9 @@ piix_init(const device_t *info)
     piix_log("PIIX%i: Added to slot: %02X\n", dev->type, dev->pci_slot);
     params.pci_dev = &dev->pci_slot;
     params.pci_conf = &dev->regs[2][0];
+    params.do_smi_raise = piix_smsc_usb_smi_raise;
+    params.priv = dev;
+    params.do_pci_irq = 0;
 
     dev->bm[0] = device_add_inst(&sff8038i_device, 1);
     dev->bm[1] = device_add_inst(&sff8038i_device, 2);
diff --git a/src/chipset/sis_5571_h2p.c b/src/chipset/sis_5571_h2p.c
index 4a4ee9b83d..b0b43310ac 100644
--- a/src/chipset/sis_5571_h2p.c
+++ b/src/chipset/sis_5571_h2p.c
@@ -276,6 +276,9 @@ sis_5571_host_to_pci_write(int addr, uint8_t val, void *priv)
             break;
 
         case 0x95: /* Test mode control */
+            dev->sis->test_mode_reg = val & 0xfb;
+            pclog("SiS: USB SMI# %sabled\n", (dev->sis->test_mode_reg & 0x10) ? "en" : "dis");
+            break;
         case 0x96: /* Time slot and Programmable 10-bit I/O port definition */
             dev->pci_conf[addr] = val & 0xfb;
             break;
@@ -309,7 +312,7 @@ sis_5571_host_to_pci_read(int addr, void *priv)
     const sis_5571_host_to_pci_t *dev = (sis_5571_host_to_pci_t *) priv;
     uint8_t ret = 0xff;
 
-    ret = dev->pci_conf[addr];
+    ret = (addr == 0x95) ? dev->sis->test_mode_reg : dev->pci_conf[addr];
 
     sis_5571_host_to_pci_log("SiS 5571 H2P: [R] dev->pci_conf[%02X] = %02X\n", addr, ret);
 
@@ -410,6 +413,8 @@ sis_5571_host_to_pci_reset(void *priv)
     dev->pci_conf[0xa2] = 0xff;
     dev->pci_conf[0xa3] = 0x00;
 
+    dev->sis->test_mode_reg = 0x10;
+
     cpu_cache_ext_enabled = 0;
     cpu_update_waitstates();
 
diff --git a/src/chipset/sis_5572_usb.c b/src/chipset/sis_5572_usb.c
index a50c8d615d..241cd0f9ff 100644
--- a/src/chipset/sis_5572_usb.c
+++ b/src/chipset/sis_5572_usb.c
@@ -66,7 +66,7 @@ sis_5572_usb_log(const char *fmt, ...)
 #endif
 
 typedef struct sis_5572_usb_t {
-    uint8_t     rev;
+    uint8_t     rev, irq_state;
 
     uint8_t     usb_unk_regs[256];
     uint8_t     pci_conf[256];
@@ -78,6 +78,30 @@ typedef struct sis_5572_usb_t {
     sis_55xx_common_t *sis;
 } sis_5572_usb_t;
 
+void
+sis_5572_usb_smi_raise(void* priv)
+{
+    sis_5572_usb_t *dev = (sis_5572_usb_t *) priv;
+    
+    if (dev->sis->usb_enabled && (dev->sis->test_mode_reg & 0x10)) {
+        dev->sis->test_mode_reg |= 0x8;
+        smi_raise();
+    }
+}
+
+void
+sis_5572_usb_pci_irq(void *priv, int level)
+{
+    sis_5572_usb_t *dev = (sis_5572_usb_t *) priv;
+    
+    if (dev->sis->usb_enabled) {
+        if (level)
+            pci_set_mirq(PCI_MIRQ3, level, &dev->irq_state);
+        else
+            pci_clear_mirq(PCI_MIRQ3, level, &dev->irq_state);
+    }
+}
+
 /* SiS 5572 unknown I/O port (second USB PCI BAR). */
 static void
 sis_5572_usb_unk_write(uint16_t addr, uint8_t val, void *priv)
@@ -275,8 +299,11 @@ sis_5572_usb_init(UNUSED(const device_t *info))
 
     /* USB */
     usb_param.pci_conf = dev->pci_conf;
-    usb_param.pci_dev = dev->sis->sb_southbridge_slot;
-    dev->usb = device_add(&usb_device);
+    usb_param.pci_dev  = dev->sis->sb_southbridge_slot;
+    usb_param.priv     = dev;
+    usb_param.do_smi_raise = sis_5572_usb_smi_raise;
+    usb_param.do_pci_irq = sis_5572_usb_pci_irq;
+    dev->usb = device_add_params(&usb_device, &usb_param);
     ohci_register_usb(dev->usb);
 
     sis_5572_usb_reset(dev);
diff --git a/src/chipset/sis_5581_h2p.c b/src/chipset/sis_5581_h2p.c
index 30bd70bfea..08451ecc0b 100644
--- a/src/chipset/sis_5581_h2p.c
+++ b/src/chipset/sis_5581_h2p.c
@@ -389,7 +389,8 @@ sis_5581_host_to_pci_write(int addr, uint8_t val, void *priv)
             break;
 
         case 0x95:
-            dev->pci_conf[addr] = val & 0xfb;
+            dev->sis->test_mode_reg = val & 0xfb;
+            pclog("SiS: USB SMI# %sabled\n", (dev->sis->test_mode_reg & 0x10) ? "en" : "dis");
             break;
 
         case 0x96:
@@ -418,7 +419,7 @@ sis_5581_host_to_pci_read(int addr, void *priv)
     const sis_5581_host_to_pci_t *dev = (sis_5581_host_to_pci_t *) priv;
     uint8_t ret = 0xff;
 
-    ret = dev->pci_conf[addr];
+    ret = (addr == 0x95) ? dev->sis->test_mode_reg : dev->pci_conf[addr];
 
     sis_5581_host_to_pci_log("SiS 5581 H2P: [R] dev->pci_conf[%02X] = %02X\n", addr, ret);
 
@@ -478,6 +479,8 @@ sis_5581_host_to_pci_reset(void *priv)
     dev->pci_conf[0xa1] = 0x00;
     dev->pci_conf[0xa2] = 0xff;
     dev->pci_conf[0xa3] = 0x00;
+    
+    dev->sis->test_mode_reg = 0x00;
 
     cpu_cache_ext_enabled = 0;
     cpu_update_waitstates();
diff --git a/src/include/86box/sis_55xx.h b/src/include/86box/sis_55xx.h
index e2ac6bd95d..d33cb8a713 100644
--- a/src/include/86box/sis_55xx.h
+++ b/src/include/86box/sis_55xx.h
@@ -22,6 +22,7 @@ typedef struct
     uint8_t    *sb_southbridge_slot;
     uint8_t     ide_bits_1_3_writable;
     uint8_t     usb_enabled;
+    uint8_t     test_mode_reg; /* USB SMI control. */
 
     uint8_t    *pmu_regs;
 
diff --git a/src/include/86box/usb.h b/src/include/86box/usb.h
index f5c3ec3c83..0404c4f253 100644
--- a/src/include/86box/usb.h
+++ b/src/include/86box/usb.h
@@ -28,6 +28,10 @@ typedef struct usb_device_c usb_device_c;
 typedef struct usb_params_t {
     uint8_t* pci_dev;
     uint8_t* pci_conf;
+
+    void* priv; /* Implementation-specific behaviour. */
+    void (*do_smi_raise)(void* priv);
+    void (*do_pci_irq)(void* priv, int level);
 } usb_params_t;
 
 typedef struct usb_t {
diff --git a/src/usb/usb_hid.c b/src/usb/usb_hid.c
index adec077fd0..d4ba52620f 100644
--- a/src/usb/usb_hid.c
+++ b/src/usb/usb_hid.c
@@ -1235,7 +1235,7 @@ usb_hid_poll_wrapper(void *priv)
 
     mouse_subtract_coords(&delta_x, &delta_y, &overflow_x, &overflow_y,
                           -128, 127, 1, 0);
-    mouse_subtract_z(&delta_z, -8, 7, 1);
+    mouse_subtract_z(&delta_z, -8, 7, 0);
     mouse_enq(hid, delta_x, delta_y, delta_z, b, 0);
     return 1;
 }
@@ -1505,7 +1505,7 @@ usb_device_hid_handle_data(usb_device_c *device, USBPacket *p)
         case USB_TOKEN_IN:
             if (p->devep == 1) {
                 if ((device->type == USB_HID_TYPE_MOUSE) || (device->type == USB_HID_TYPE_TABLET)) {
-                    pclog("USB MOUSE POLLING\n");
+                    //pclog("USB MOUSE POLLING\n");
                     ret = usb_mouse_poll((usb_device_hid *) device, p->data, 0);
                 } else {
                     goto fail;
diff --git a/src/usb/usb_ohci_bochs.c b/src/usb/usb_ohci_bochs.c
index 152e68e911..c450c51c4e 100644
--- a/src/usb/usb_ohci_bochs.c
+++ b/src/usb/usb_ohci_bochs.c
@@ -196,6 +196,8 @@ typedef struct {
       bool   oci;               //  1 bit OverCurrentIndicator        = 0b             R   RW
       bool   lps;               //  1 bit LocalPowerStatus(r)         = 0b             RW  R
     } HcRhStatus;               //                                    = 0x00000000
+
+    uint32_t HceInput, HceOutput, HceControl, HceStatus;
   } op_regs;
 
   struct {
@@ -235,6 +237,10 @@ typedef struct {
 
   bool ohci_enable;
   uint32_t ohci_mem_base;
+
+  void (*do_smi_raise)(void *priv);
+  void (*do_pci_irq)(void *priv, int level);
+  void* card_priv;
 } bx_ohci_core_t;
 
 const char *usb_ohci_port_name[] = {
@@ -301,13 +307,19 @@ void usb_ohci_update_irq(bx_ohci_core_t* hub)
       (hub->op_regs.HcInterruptStatus & hub->op_regs.HcInterruptEnable)) {
       level = 1;
   }
-  if (hub->op_regs.HcControl.ir && level)
-    smi_raise();
+  if (hub->op_regs.HcControl.ir && level) {
+    if (hub->do_smi_raise && hub->card_priv)
+      hub->do_smi_raise(hub->card_priv);
+    else        
+      smi_raise();
+  }
   else if (!hub->op_regs.HcControl.ir) {
-    if (level)
+    if (hub->do_pci_irq)
+      hub->do_pci_irq(hub->card_priv, level);
+    else if (level)
       pci_set_irq(*hub->devfunc, hub->pci_conf[0x3d], &hub->irq_state);
     else
-      pci_set_irq(*hub->devfunc, hub->pci_conf[0x3d], &hub->irq_state);
+      pci_clear_irq(*hub->devfunc, hub->pci_conf[0x3d], &hub->irq_state);
   }
 }
 
@@ -767,6 +779,26 @@ uint32_t usb_ohci_mem_read(uint32_t addr, void *priv)
             | (hub->usb_port[p].HcRhPortStatus.ccs       ? (1 <<  0) : 0);
       break;
 
+    case 0x100: {
+      val = (hub->op_regs.HceControl & 0xFF) | ((!!mem_a20_key) << 8);
+      break;
+    }
+
+    case 0x104: {
+      val = hub->op_regs.HceInput;
+      break;
+    }
+
+    case 0x108: {
+      val = hub->op_regs.HceOutput;
+      break;
+    }
+
+    case 0x10C: {
+      val = hub->op_regs.HceStatus;
+      break;
+    }
+
     default:
       BX_ERROR(("unsupported read from address=0x%08X!", (Bit32u)addr));
       break;
@@ -836,7 +868,10 @@ void usb_ohci_mem_write(uint32_t addr, uint32_t value, void* priv)
         hub->op_regs.HcInterruptStatus |= 0x40000000;
         if ((hub->op_regs.HcInterruptEnable & 0xC0000000) == 0xC0000000) {
           pclog("Assert SMI#\n");
-          smi_raise();
+          if (hub->do_smi_raise && hub->card_priv)
+            hub->do_smi_raise(hub->card_priv);
+          else
+            smi_raise();
         }
       }
       if (value & (1<< 2)) hub->op_regs.HcCommandStatus.blf = 1;
@@ -1094,6 +1129,25 @@ void usb_ohci_mem_write(uint32_t addr, uint32_t value, void* priv)
       break;
     }
 
+    case 0x100: {
+      hub->op_regs.HceControl = value;
+      break;
+    }
+
+    case 0x104: {
+      hub->op_regs.HceInput = value;
+      break;
+    }
+
+    case 0x108: {
+      hub->op_regs.HceOutput = value;
+      break;
+    }
+
+    case 0x10C: {
+      hub->op_regs.HceStatus = value;
+      break;
+    }
 
     default:
       BX_ERROR(("unsupported write to address=0x%08X, val = 0x%08X!", (Bit32u)addr, value));
@@ -1593,6 +1647,9 @@ usb_ohci_init(UNUSED(const device_t *info))
     if (usb_params) {
       hub->devfunc = usb_params->pci_dev;
       hub->pci_conf = usb_params->pci_conf;
+      hub->do_smi_raise = usb_params->do_smi_raise;
+      hub->card_priv = usb_params->priv;
+      hub->do_pci_irq = usb_params->do_pci_irq;
     }
     timer_add(&hub->timer, usb_ohci_timer, hub, 0);
     timer_on_auto(&hub->timer, 1000);