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* [PATCH] 2.6.0-test4 Don't change BIOS allocated IRQs
@ 2003-09-16 23:11 ` Andrew de Quincey
  0 siblings, 0 replies; 8+ messages in thread
From: Andrew de Quincey @ 2003-09-16 23:11 UTC (permalink / raw)
  To: linux-kernel-u79uwXL29TY76Z2rM5mHXA,
	acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f
  Cc: linux-acpi-ral2JQCrhuEAvxtiuMwx3w, Chris Wright

With the help of Chris Wright testing several failed patches, I've tracked 
down another ACPI IRQ problem. On many systems, the BIOS 
pre-allocates IRQs for certain PCI devices, providing a list of alternate 
possibilities as well.

On some systems, changing the IRQ to one of those alternate possibilities 
works fine. On others however, it really isn't a good idea. As theres no 
way to tell which systems are good and bad in advance, this patch simply 
ensures that ACPI does not change an IRQ if the BIOS has pre-allocated it.



--- linux-2.6.0-test4.es7000fix/drivers/acpi/pci_link.c	2003-09-06 00:35:16.000000000 +0100
+++ linux-2.6.0-test4.nochangeirq/drivers/acpi/pci_link.c	2003-09-17 00:00:40.740553544 +0100
@@ -510,15 +510,15 @@
 		irq = link->irq.active;
 	} else {
 		irq = link->irq.possible[0];
-	}
 
-	/* 
-	 * Select the best IRQ.  This is done in reverse to promote 
-	 * the use of IRQs 9, 10, 11, and >15.
-	 */
-	for (i=(link->irq.possible_count-1); i>0; i--) {
-		if (acpi_irq_penalty[irq] > acpi_irq_penalty[link->irq.possible[i]])
-			irq = link->irq.possible[i];
+		/* 
+		 * Select the best IRQ.  This is done in reverse to promote 
+		 * the use of IRQs 9, 10, 11, and >15.
+		 */
+		for (i=(link->irq.possible_count-1); i>0; i--) {
+			if (acpi_irq_penalty[irq] > acpi_irq_penalty[link->irq.possible[i]])
+				irq = link->irq.possible[i];
+		}
 	}
 
 	/* Attempt to enable the link device at this IRQ. */

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2003-09-17  8:08 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2003-09-16 23:11 [PATCH] 2.6.0-test4 Don't change BIOS allocated IRQs Andrew de Quincey
2003-09-16 23:11 ` Andrew de Quincey
     [not found] ` <200309170011.03630.adq_dvb-fmPXVN3awWJAJAzL26g0SA@public.gmane.org>
2003-09-17  0:29   ` Chris Wright
2003-09-17  0:29     ` Chris Wright
2003-09-17  1:02   ` [ACPI] " Greg KH
2003-09-17  1:02     ` Greg KH
2003-09-17  8:08     ` Andrew de Quincey
     [not found]     ` <20030917010254.GA1640-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2003-09-17  8:08       ` Andrew de Quincey

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