Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U8

[Michal Schmidt]

Ingo Molnar wrote:
> * Michal Schmidt <xschmi00@xxxxxxxxxxxxxxxxxx> wrote:
> > I'm getting these BUGs when I use netconsole with Real-Time Preemption
> > (but netconsole works):
>
>
> you are getting them because interrupts get disabled somewhere in the
> path. Do your changes perhaps introduce a local_irq_save() or
> local_irq_disable()?

I'm attaching my sk98lin patch. It uses disable_irq(). It's inspired by 
8139too.

> (in PREEMPT_REALTIME spin_lock_irq*() does not disable interrupts for
> mutex-based spinlocks, so the only way to get irqs disabled is
> explicitly.)
>
> 	Ingo

Michal
diff -Nurp linux-2.6.9/drivers/net/sk98lin/skge.c linux-2.6.9-mich/drivers/net/sk98lin/skge.c
--- linux-2.6.9/drivers/net/sk98lin/skge.c	2004-10-18 23:53:22.000000000 +0200
+++ linux-2.6.9-mich/drivers/net/sk98lin/skge.c	2004-10-20 01:09:07.566181320 +0200
@@ -1126,6 +1126,21 @@ SK_U32		IntSrc;		/* interrupts source re
 		return SkIsrRetHandled;
 } /* SkGeIsrOnePort */
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+/**
+ * SkGePollController - polling receive, for netconsole
+ * @dev: network device
+ *
+ * Polling receive - used by netconsole and other diagnostic tools
+ * to allow network i/o with interrupts disabled.
+ */
+static void SkGePollController(struct net_device *dev)
+{
+	disable_irq(dev->irq);
+	SkGeIsr(dev->irq, dev, NULL);
+	enable_irq(dev->irq);
+}
+#endif
 
 /****************************************************************************
  *
@@ -4960,6 +4975,9 @@ static int __devinit skge_probe_one(stru
 	dev->set_mac_address =	&SkGeSetMacAddr;
 	dev->do_ioctl =		&SkGeIoctl;
 	dev->change_mtu =	&SkGeChangeMtu;
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	dev->poll_controller =	&SkGePollController;
+#endif
 	dev->flags &= 		~IFF_RUNNING;
 	SET_NETDEV_DEV(dev, &pdev->dev);