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yaml
---
r: 116453
b: refs/heads/master
c: 3eb2cce
h: refs/heads/master
i:
  116451: efa6698
v: v3
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Yinghai Lu authored and Ingo Molnar committed Oct 16, 2008
1 parent 70a6085 commit eefa787
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Showing 2 changed files with 36 additions and 39 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 4e738e2f307113feaedebae147c3e0d072e39648
refs/heads/master: 3eb2cce84beae8fd41de950569cafd5bca7edd5d
73 changes: 35 additions & 38 deletions trunk/arch/x86/kernel/io_apic.c
Original file line number Diff line number Diff line change
Expand Up @@ -389,7 +389,6 @@ static inline void io_apic_modify(unsigned int apic, unsigned int reg, unsigned
writel(value, &io_apic->data);
}

#ifdef CONFIG_X86_64
static bool io_apic_level_ack_pending(unsigned int irq)
{
struct irq_pin_list *entry;
Expand Down Expand Up @@ -419,7 +418,6 @@ static bool io_apic_level_ack_pending(unsigned int irq)

return false;
}
#endif

union entry_union {
struct { u32 w1, w2; };
Expand Down Expand Up @@ -2398,9 +2396,16 @@ static void ack_apic_edge(unsigned int irq)
ack_APIC_irq();
}

#ifdef CONFIG_X86_64
#ifdef CONFIG_X86_32
atomic_t irq_mis_count;
#endif

static void ack_apic_level(unsigned int irq)
{
#ifdef CONFIG_X86_32
unsigned long v;
int i;
#endif
int do_unmask_irq = 0;

irq_complete_move(irq);
Expand All @@ -2412,6 +2417,31 @@ static void ack_apic_level(unsigned int irq)
}
#endif

#ifdef CONFIG_X86_32
/*
* It appears there is an erratum which affects at least version 0x11
* of I/O APIC (that's the 82093AA and cores integrated into various
* chipsets). Under certain conditions a level-triggered interrupt is
* erroneously delivered as edge-triggered one but the respective IRR
* bit gets set nevertheless. As a result the I/O unit expects an EOI
* message but it will never arrive and further interrupts are blocked
* from the source. The exact reason is so far unknown, but the
* phenomenon was observed when two consecutive interrupt requests
* from a given source get delivered to the same CPU and the source is
* temporarily disabled in between.
*
* A workaround is to simulate an EOI message manually. We achieve it
* by setting the trigger mode to edge and then to level when the edge
* trigger mode gets detected in the TMR of a local APIC for a
* level-triggered interrupt. We mask the source for the time of the
* operation to prevent an edge-triggered interrupt escaping meanwhile.
* The idea is from Manfred Spraul. --macro
*/
i = irq_cfg(irq)->vector;

v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));
#endif

/*
* We must acknowledge the irq before we move it or the acknowledge will
* not propagate properly.
Expand Down Expand Up @@ -2450,50 +2480,17 @@ static void ack_apic_level(unsigned int irq)
move_masked_irq(irq);
unmask_IO_APIC_irq(irq);
}
}
#else
atomic_t irq_mis_count;
static void ack_apic_level(unsigned int irq)
{
unsigned long v;
int i;

irq_complete_move(irq);
move_native_irq(irq);
/*
* It appears there is an erratum which affects at least version 0x11
* of I/O APIC (that's the 82093AA and cores integrated into various
* chipsets). Under certain conditions a level-triggered interrupt is
* erroneously delivered as edge-triggered one but the respective IRR
* bit gets set nevertheless. As a result the I/O unit expects an EOI
* message but it will never arrive and further interrupts are blocked
* from the source. The exact reason is so far unknown, but the
* phenomenon was observed when two consecutive interrupt requests
* from a given source get delivered to the same CPU and the source is
* temporarily disabled in between.
*
* A workaround is to simulate an EOI message manually. We achieve it
* by setting the trigger mode to edge and then to level when the edge
* trigger mode gets detected in the TMR of a local APIC for a
* level-triggered interrupt. We mask the source for the time of the
* operation to prevent an edge-triggered interrupt escaping meanwhile.
* The idea is from Manfred Spraul. --macro
*/
i = irq_cfg(irq)->vector;

v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));

ack_APIC_irq();

#ifdef CONFIG_X86_32
if (!(v & (1 << (i & 0x1f)))) {
atomic_inc(&irq_mis_count);
spin_lock(&ioapic_lock);
__mask_and_edge_IO_APIC_irq(irq);
__unmask_and_level_IO_APIC_irq(irq);
spin_unlock(&ioapic_lock);
}
}
#endif
}

static struct irq_chip ioapic_chip __read_mostly = {
.name = "IO-APIC",
Expand Down

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