The 2.6.31 kernel has threaded IRQ support and b43 is the first
wireless driver that makes use of it. To support threaded IRSs
on older kernels we built our own struct compat_threaded_irq
to queue_work() onto it as the kernel thread be running the
thread in process context as well.

--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -4184,8 +4184,13 @@ redo:
 	if (b43_bus_host_is_sdio(dev->dev)) {
 		b43_sdio_free_irq(dev);
 	} else {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+		compat_synchronize_threaded_irq(&dev->irq_compat);
+		compat_free_threaded_irq(&dev->irq_compat);
+#else
 		synchronize_irq(dev->dev->irq);
 		free_irq(dev->dev->irq, dev);
+#endif
 	}
 	mutex_lock(&wl->mutex);
 	dev = wl->current_dev;
@@ -4225,9 +4230,17 @@ static int b43_wireless_core_start(struc
 			goto out;
 		}
 	} else {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+		err = compat_request_threaded_irq(&dev->irq_compat,
+						  dev->dev->irq,
+						  b43_interrupt_handler,
+						  b43_interrupt_thread_handler,
+						  IRQF_SHARED, KBUILD_MODNAME, dev);
+#else
 		err = request_threaded_irq(dev->dev->irq, b43_interrupt_handler,
 					   b43_interrupt_thread_handler,
 					   IRQF_SHARED, KBUILD_MODNAME, dev);
+#endif
 		if (err) {
 			b43err(dev->wl, "Cannot request IRQ-%d\n",
 			       dev->dev->irq);
@@ -5016,6 +5029,10 @@ static int b43_setup_bands(struct b43_wl
 
 static void b43_wireless_core_detach(struct b43_wldev *dev)
 {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+	if (dev->dev->sdev->bus->bustype != SSB_BUSTYPE_SDIO)
+		compat_destroy_threaded_irq(&dev->irq_compat);
+#endif
 	/* We release firmware that late to not be required to re-request
 	 * is all the time when we reinit the core. */
 	b43_release_firmware(dev);
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -843,6 +843,9 @@ struct b43_wldev {
 	unsigned int tx_count;
 	unsigned int rx_count;
 #endif
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+	struct compat_threaded_irq irq_compat;
+#endif
 };
 
 /* Data structure for the WLAN parts (802.11 cores) of the b43 chip. */
--- a/drivers/net/wireless/wl12xx/spi.c
+++ b/drivers/net/wireless/wl12xx/spi.c
@@ -406,10 +406,14 @@ static int __devinit wl1271_probe(struct
 	wl->tcxo_clock = pdata->board_tcxo_clock;
 	wl->platform_quirks = pdata->platform_quirks;
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
+	irqflags = IRQF_TRIGGER_RISING;
+#else
 	if (wl->platform_quirks & WL12XX_PLATFORM_QUIRK_EDGE_IRQ)
 		irqflags = IRQF_TRIGGER_RISING;
 	else
 		irqflags = IRQF_TRIGGER_HIGH | IRQF_ONESHOT;
+#endif
 
 	wl->irq = spi->irq;
 	if (wl->irq < 0) {
@@ -418,9 +422,16 @@ static int __devinit wl1271_probe(struct
 		goto out_free;
 	}
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+	ret = compat_request_threaded_irq(&wl->irq_compat, wl->irq,
+					  wl1271_hardirq, wl1271_irq,
+					  irqflags,
+					  DRIVER_NAME, wl);
+#else
 	ret = request_threaded_irq(wl->irq, wl1271_hardirq, wl1271_irq,
 				   irqflags,
 				   DRIVER_NAME, wl);
+#endif
 	if (ret < 0) {
 		wl1271_error("request_irq() failed: %d", ret);
 		goto out_free;
@@ -439,7 +450,11 @@ static int __devinit wl1271_probe(struct
 	return 0;
 
  out_irq:
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+	compat_free_threaded_irq(&wl->irq_compat);
+#else
 	free_irq(wl->irq, wl);
+#endif
 
  out_free:
 	wl1271_free_hw(wl);
@@ -452,7 +467,12 @@ static int __devexit wl1271_remove(struc
 	struct wl1271 *wl = dev_get_drvdata(&spi->dev);
 
 	wl1271_unregister_hw(wl);
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+	compat_free_threaded_irq(&wl->irq_compat);
+	compat_destroy_threaded_irq(&wl->irq_compat);
+#else
 	free_irq(wl->irq, wl);
+#endif
 	wl1271_free_hw(wl);
 
 	return 0;
--- a/drivers/net/wireless/wl12xx/wl12xx.h
+++ b/drivers/net/wireless/wl12xx/wl12xx.h
@@ -632,6 +632,10 @@ struct wl1271 {
 
 	/* AP-mode - number of currently connected stations */
 	int active_sta_count;
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31)
+	struct compat_threaded_irq irq_compat;
+#endif
 };
 
 struct wl1271_station {