[PATCH] Fix HPET operation on 64-bit NVIDIA platforms
From: "Andy Currid" <ACurrid@nvidia.com>
This patch fixes a kernel panic during boot that occurs on NVIDIA platforms
that have HPET enabled.
When HPET is enabled, the standard timer IRQ is routed to IOAPIC pin 2 and is
advertised as such in the ACPI APIC table - but an earlier workaround in the
kernel was ignoring this override. The fix is to honor timer IRQ overrides
from ACPI when HPET is detected on an NVIDIA platform.
Signed-off-by: Andy Currid <acurrid@nvidia.com>
Cc: "Brown, Len" <len.brown@intel.com>
Cc: "Yu, Luming" <luming.yu@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 0de3ea9..9cc7031 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/arch/x86_64/kernel/io_apic.c
@@ -271,6 +271,18 @@
#include <linux/pci_ids.h>
#include <linux/pci.h>
+
+#ifdef CONFIG_ACPI
+
+static int nvidia_hpet_detected __initdata;
+
+static int __init nvidia_hpet_check(unsigned long phys, unsigned long size)
+{
+ nvidia_hpet_detected = 1;
+ return 0;
+}
+#endif
+
/* Temporary Hack. Nvidia and VIA boards currently only work with IO-APIC
off. Check for an Nvidia or VIA PCI bridge and turn it off.
Use pci direct infrastructure because this runs before the PCI subsystem.
@@ -317,11 +329,19 @@
return;
case PCI_VENDOR_ID_NVIDIA:
#ifdef CONFIG_ACPI
- /* All timer overrides on Nvidia
- seem to be wrong. Skip them. */
- acpi_skip_timer_override = 1;
- printk(KERN_INFO
- "Nvidia board detected. Ignoring ACPI timer override.\n");
+ /*
+ * All timer overrides on Nvidia are
+ * wrong unless HPET is enabled.
+ */
+ nvidia_hpet_detected = 0;
+ acpi_table_parse(ACPI_HPET,
+ nvidia_hpet_check);
+ if (nvidia_hpet_detected == 0) {
+ acpi_skip_timer_override = 1;
+ printk(KERN_INFO "Nvidia board "
+ "detected. Ignoring ACPI "
+ "timer override.\n");
+ }
#endif
/* RED-PEN skip them on mptables too? */
return;