diff -Naur linux-2.6.8-01/drivers/net/wireless/prism54/islpci_dev.c linux-2.6.8-02/drivers/net/wireless/prism54/islpci_dev.c
--- linux-2.6.8-01/drivers/net/wireless/prism54/islpci_dev.c	2004-07-28 13:58:06.000000000 +0200
+++ linux-2.6.8-02/drivers/net/wireless/prism54/islpci_dev.c	2004-07-28 14:04:08.000000000 +0200
@@ -186,6 +186,9 @@
 	void *device = priv->device_base;
 	int powerstate = ISL38XX_PSM_POWERSAVE_STATE;
 
+	/* lock the interrupt handler */
+	spin_lock(&priv->slock);
+
 	/* received an interrupt request on a shared IRQ line
 	 * first check whether the device is in sleep mode */
 	reg = readl(device + ISL38XX_CTRL_STAT_REG);
@@ -195,14 +198,10 @@
 #if VERBOSE > SHOW_ERROR_MESSAGES
 		DEBUG(SHOW_TRACING, "Assuming someone else called the IRQ\n");
 #endif
+		spin_unlock(&priv->slock);
 		return IRQ_NONE;
 	}
 
-	if (islpci_get_state(priv) != PRV_STATE_SLEEP)
-		powerstate = ISL38XX_PSM_ACTIVE_STATE;
-
-	/* lock the interrupt handler */
-	spin_lock(&priv->slock);
 
 	/* check whether there is any source of interrupt on the device */
 	reg = readl(device + ISL38XX_INT_IDENT_REG);
@@ -213,6 +212,9 @@
 	reg &= ISL38XX_INT_SOURCES;
 
 	if (reg != 0) {
+		if (islpci_get_state(priv) != PRV_STATE_SLEEP)
+			powerstate = ISL38XX_PSM_ACTIVE_STATE;
+
 		/* reset the request bits in the Identification register */
 		isl38xx_w32_flush(device, reg, ISL38XX_INT_ACK_REG);
 
@@ -340,6 +342,12 @@
 			isl38xx_handle_wakeup(priv->control_block,
 					      &powerstate, priv->device_base);
 		}
+	} else {
+#if VERBOSE > SHOW_ERROR_MESSAGES
+		DEBUG(SHOW_TRACING, "Assuming someone else called the IRQ\n");
+#endif
+		spin_unlock(&priv->slock);
+		return IRQ_NONE;
 	}
 
 	/* sleep -> ready */