Re: [Qemu-devel] [PATCH] Update i440FX/PIIX3 emulation

[Michael Hanselmann <qemu@hansmi.ch>]

On Thu, Oct 25, 2007 at 12:42:22AM +0200, Michael Hanselmann wrote:
> The patch below updates the i440FX/PIIX3 emulation. It does:

I never got any reaction to that patch. Is it still awaiting review?

> This does not yet remove the workaround introduced by Igor Lvovsky's
> patch. However, I'm working on that since it, despite my earlier mail,
> seems to help with my ACPI shutdown problem.

So, I found the bug causing this behaviour. It turned out to be a
wrongly named variable in the ACPI DSDT from Bochs. See the patch for
Bochs below. I already sent it to the bochs-developers list[1].
qemu/pc-bios/bios.bin needs to be rebuilt from Bochs' code,
qemu/pc-bios/bios.diff and my patch.

The second patch below reverts the changes made by Igor Lvovsky. After
applying the patch to the BIOS, ACPI IRQs finally reach the system.

Finding this bug took me about the free time of four weeks. However, I
learned a lot about the internals of a PC. :-)

Thanks,
Michael

[1] http://sourceforge.net/mailarchive/forum.php?thread_name=20071031000835.GA20915%40hansmi.ch&forum_name=bochs-developers

---
Index: bios/acpi-dsdt.dsl
===================================================================
RCS file: /cvsroot/bochs/bochs/bios/acpi-dsdt.dsl,v
retrieving revision 1.1
diff -u -p -u -p -r1.1 acpi-dsdt.dsl
--- bios/acpi-dsdt.dsl	28 Sep 2006 18:56:20 -0000	1.1
+++ bios/acpi-dsdt.dsl	30 Oct 2007 23:52:22 -0000
@@ -369,7 +369,7 @@ DefinitionBlock (
                 Method (_STA, 0, NotSerialized)
                 {
                     Store (0x0B, Local0)
-                    If (And (0x80, PRQ0, Local1))
+                    If (And (0x80, PRQ0, Local0))
                     {
                          Store (0x09, Local0)
                     }
@@ -416,7 +416,7 @@ DefinitionBlock (
                 Method (_STA, 0, NotSerialized)
                 {
                     Store (0x0B, Local0)
-                    If (And (0x80, PRQ1, Local1))
+                    If (And (0x80, PRQ1, Local0))
                     {
                          Store (0x09, Local0)
                     }
@@ -463,7 +463,7 @@ DefinitionBlock (
                 Method (_STA, 0, NotSerialized)
                 {
                     Store (0x0B, Local0)
-                    If (And (0x80, PRQ2, Local1))
+                    If (And (0x80, PRQ2, Local0))
                     {
                          Store (0x09, Local0)
                     }
@@ -510,7 +510,7 @@ DefinitionBlock (
                 Method (_STA, 0, NotSerialized)
                 {
                     Store (0x0B, Local0)
-                    If (And (0x80, PRQ3, Local1))
+                    If (And (0x80, PRQ3, Local0))
                     {
                          Store (0x09, Local0)
                     }

---
diff --git a/hw/piix_pci.c b/hw/piix_pci.c
index 7c7d0f3..eabff8e 100644
--- a/hw/piix_pci.c
+++ b/hw/piix_pci.c
@@ -269,7 +269,6 @@ static void piix3_set_irq(qemu_irq *pic, int irq_num, int level)
 {
     int i, pic_irq, pic_level;
 
-    piix3_dev->config[0x60 + irq_num] &= ~0x80;
     pci_irq_levels[irq_num] = level;
 
     /* now we change the pic irq level according to the piix irq mappings */