Fix the shared irq problem, by allocating a low priority vector

so that the "high" pri interrupt gets blocked by the "low" spl & irq handler,
and raise the cpl to the "high" level in the handler, so that no other
in fact lower-leveled, interrupts can preempt the handling of the "high"
interrupt.  This means that the "low" interrupt gets the same quality treatment,
thus causing some degradation in performance.  Therefore we still issue a
diagnostic, so people can try to avoid the situation by tweaking their BIOS
settings. Note, there is still issues with dynamically established interrupts
which cause irq sharing, we are working on that.

2 files changed, 12 insertions, 13 deletions

diff --git a/sys/arch/i386/i386/apicvec.s b/sys/arch/i386/i386/apicvec.s
index 4ab84c31def..59f3744052e 100644
--- a/sys/arch/i386/i386/apicvec.s
+++ b/sys/arch/i386/i386/apicvec.s
@@ -1,4 +1,4 @@
-/* $OpenBSD: apicvec.s,v 1.3 2004/06/28 02:00:20 deraadt Exp $ */	
+/* $OpenBSD: apicvec.s,v 1.4 2004/08/12 06:11:57 niklas Exp $ */	
 /* $NetBSD: apicvec.s,v 1.1.2.2 2000/02/21 21:54:01 sommerfeld Exp $ */	
 
 /*-
@@ -179,12 +179,13 @@ _C_LABEL(Xintr_/**/name/**/num):					\
 	MAKE_FRAME							;\
 	pushl	CPL							;\
 	movl	_C_LABEL(lapic_ppr),%eax				;\
-	movl	%eax,CPL						;\
+	orl	$num,%eax						;\
+	movl	_C_LABEL(apic_maxlevel)(,%eax,4),%ebx			;\
+	movl	%ebx,CPL						;\
 	mask(num)			/* mask it in hardware */	;\
 	early_ack(num)			/* and allow other intrs */	;\
 	incl	MY_COUNT+V_INTR		/* statistical info */		;\
 	sti								;\
-	orl	$num,%eax						;\
 	incl	_C_LABEL(apic_intrcount)(,%eax,4)			;\
 	movl	_C_LABEL(apic_intrhand)(,%eax,4),%ebx /* chain head */	;\
 	testl	%ebx,%ebx						;\
diff --git a/sys/arch/i386/i386/ioapic.c b/sys/arch/i386/i386/ioapic.c
index 0ec3795e0c4..abb77edfb6e 100644
--- a/sys/arch/i386/i386/ioapic.c
+++ b/sys/arch/i386/i386/ioapic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ioapic.c,v 1.4 2004/06/28 01:41:53 aaron Exp $	*/
+/*	$OpenBSD: ioapic.c,v 1.5 2004/08/12 06:11:57 niklas Exp $	*/
 /* 	$NetBSD: ioapic.c,v 1.7 2003/07/14 22:32:40 lukem Exp $	*/
 
 /*-
@@ -354,6 +354,7 @@ ioapic_attach(struct device *parent, struct device *self, void *aux)
 
 struct intrhand *apic_intrhand[256];
 int	apic_intrcount[256];
+int	apic_maxlevel[256];
 
 
 /* XXX should check vs. softc max int number */
@@ -459,14 +460,10 @@ apic_vectorset(struct ioapic_softc *sc, int pin, int minlevel, int maxlevel)
 		pp->ip_maxlevel = 0; /* XXX magic */
 		pp->ip_vector = 0;
 	} else if (maxlevel != pp->ip_maxlevel) {
-		if (minlevel != maxlevel) {
-			printf("%s: WARNING: sharing interrupt "
-			    "between different IPLs (currently broken)\n",
-			    sc->sc_dev.dv_xname);
-			printf("%s: pin %d, ipls %x..%x\n",
-			    sc->sc_dev.dv_xname,
-			    pin, minlevel, maxlevel);
-		}
+		if (minlevel != maxlevel)
+			printf("%s: pin %d shares different IPL interrupts "
+			    "(%x..%x), degraded performance\n",
+			    sc->sc_dev.dv_xname, pin, minlevel, maxlevel);
 
 		/*
 		 * Allocate interrupt vector at the *lowest* priority level
@@ -475,7 +472,7 @@ apic_vectorset(struct ioapic_softc *sc, int pin, int minlevel, int maxlevel)
 		 * The interrupt handler will raise ipl higher than this
 		 * as appropriate.
 		 */
-		nvector = idt_vec_alloc(maxlevel, maxlevel+15);
+		nvector = idt_vec_alloc(minlevel, minlevel+15);
 
 		if (nvector == 0) {
 			/*
@@ -486,6 +483,7 @@ apic_vectorset(struct ioapic_softc *sc, int pin, int minlevel, int maxlevel)
 			panic("%s: can't alloc vector for pin %d at level %x",
 			    sc->sc_dev.dv_xname, pin, maxlevel);
 		}
+		apic_maxlevel[nvector] = maxlevel;
 		/* 
 		 * XXX want special handler for the maxlevel != minlevel
 		 * case here!