do we have 64bit system with sis chipset?
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
---
arch/x86/kernel/io_apic_64.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)
Index: linux-2.6/arch/x86/kernel/io_apic_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/io_apic_64.c
+++ linux-2.6/arch/x86/kernel/io_apic_64.c
@@ -65,7 +65,11 @@
int ioapic_force;
-int sis_apic_bug; /* not actually supported, dummy for compile */
+/*
+ * Is the SiS APIC rmw bug present ?
+ * -1 = don't know, 0 = no, 1 = yes
+ */
+int sis_apic_bug = -1;
static DEFINE_SPINLOCK(ioapic_lock);
static DEFINE_SPINLOCK(vector_lock);
@@ -373,9 +377,11 @@ static inline void io_apic_write(unsigne
* Re-write a value: to be used for read-modify-write
* cycles where the read already set up the index register.
*/
-static inline void io_apic_modify(unsigned int apic, unsigned int value)
+static inline void io_apic_modify(unsigned int apic, unsigned int reg, unsigned int value)
{
struct io_apic __iomem *io_apic = io_apic_base(apic);
+ if (sis_apic_bug)
+ writel(reg, &io_apic->index);
writel(value, &io_apic->data);
}
@@ -494,7 +500,7 @@ static void __target_IO_APIC_irq(unsigne
reg = io_apic_read(apic, 0x10 + pin*2);
reg &= ~IO_APIC_REDIR_VECTOR_MASK;
reg |= vector;
- io_apic_modify(apic, reg);
+ io_apic_modify(apic, 0x10 + pin*2, reg);
if (!entry->next)
break;
entry = entry->next;
@@ -622,7 +628,7 @@ static inline void io_apic_sync(unsigned
pin = entry->pin; \
reg = io_apic_read(entry->apic, 0x10 + R + pin*2); \
reg ACTION; \
- io_apic_modify(entry->apic, reg); \
+ io_apic_modify(entry->apic, 0x10 + R + pin*2, reg); \
FINAL; \
if (!entry->next) \
break; \
@@ -2446,6 +2452,20 @@ void __init setup_IO_APIC(void)
check_timer();
}
+/*
+ * Called after all the initialization is done. If we didnt find any
+ * APIC bugs then we can allow the modify fast path
+ */
+
+static int __init io_apic_bug_finalize(void)
+{
+ if (sis_apic_bug == -1)
+ sis_apic_bug = 0;
+ return 0;
+}
+
+late_initcall(io_apic_bug_finalize);
+
struct sysfs_ioapic_data {
struct sys_device dev;
struct IO_APIC_route_entry entry[0];
--
