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[Qemu-devel] [PATCH v7 07/10] i8254/i8259: workaround to make IRQ0 work
From: |
Matthew Ogilvie |
Subject: |
[Qemu-devel] [PATCH v7 07/10] i8254/i8259: workaround to make IRQ0 work like before |
Date: |
Sun, 25 Nov 2012 14:51:43 -0700 |
Someday it should be fixed properly, but doing so may
break migration. So go with an incremental approach instead.
Signed-off-by: Matthew Ogilvie <address@hidden>
---
hw/i8259.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/hw/i8259.c b/hw/i8259.c
index 9b2ec40..71cc09a 100644
--- a/hw/i8259.c
+++ b/hw/i8259.c
@@ -150,8 +150,25 @@ static void pic_set_irq(void *opaque, int irq, int level)
/* Dropping level clears the interrupt regardless of edge trigger
* vs level trigger.
*/
- s->irr &= ~mask;
s->last_irr &= ~mask;
+
+ /* Migration compatibility hack:
+ *
+ * The i8254 timer model is wrong in a number of ways,
+ * including lowering IRQ0 much earlier than it should.
+ *
+ * FIXME i8254_timing_fixes: Eventually the i8254
+ * should be fixed, but it isn't
+ * trivial to do so in a way that avoids possible problems with
+ * migration (lost or gained timer ticks). So for now, make the
+ * i8254 work the same way that it worked in qemu 1.2, and
+ * leave irr for IRQ0 alone in the i8259 here:
+ */
+ if (irq == 0 && s->master) {
+ mask = 0;
+ }
+
+ s->irr &= ~mask;
}
pic_update_irq(s);
}
--
1.7.10.2.484.gcd07cc5
- [Qemu-devel] [PATCH v7 00/10] i8254, i8259 and running Microport UNIX (ca 1987), Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 01/10] fix some debug printf format strings, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 05/10] i8259: fix so that dropping IRQ level always clears the interrupt request, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 07/10] i8254/i8259: workaround to make IRQ0 work like before,
Matthew Ogilvie <=
- [Qemu-devel] [PATCH v7 02/10] vl: fix -hdachs/-hda argument order parsing issues, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 08/10] i8254: add comments about fixing timings, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 03/10] qemu-options.hx: mention retrace= VGA option, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 04/10] vga: add some optional CGA compatibility hacks, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 06/10] i8259: refactor pic_set_irq level logic, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 09/10] i8254: prepare for migration compatibility with future fixes, Matthew Ogilvie, 2012/11/25
- [Qemu-devel] [PATCH v7 10/10] FOR FUTURE: fix i8254/i8259 IRQ0 line logic, Matthew Ogilvie, 2012/11/25