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x86/ioapic.c: remove #ifdef for 82093AA workaround 

While no 64-bit hardware will have a version 0x11 I/O APIC which needs
the level/edge bug workaround, that's not a particular reason to use
CONFIG_X86_32 to #ifdef the code out.  Most 32-bit machines will no
longer need the workaround either, so the test to see whether it is
necessary should be more fine-grained than "32-bit=yes, 64-bit=no".

(Also fix formatting of block comment.)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
This commit is contained in:
Jeremy Fitzhardinge 2009-06-08 03:00:22 -07:00
parent 890aeacf64
commit 916a0fe739
1 changed files with 19 additions and 28 deletions
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47
arch/x86/kernel/apic/io_apic.c
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@ -596,7 +596,6 @@ static void __mask_IO_APIC_irq(struct irq_cfg *cfg)
io_apic_modify_irq(cfg, ~0, IO_APIC_REDIR_MASKED, &io_apic_sync);
}
#ifdef CONFIG_X86_32
static void __mask_and_edge_IO_APIC_irq(struct irq_cfg *cfg)
{
io_apic_modify_irq(cfg, ~IO_APIC_REDIR_LEVEL_TRIGGER,
@ -608,7 +607,6 @@ static void __unmask_and_level_IO_APIC_irq(struct irq_cfg *cfg)
io_apic_modify_irq(cfg, ~IO_APIC_REDIR_MASKED,
IO_APIC_REDIR_LEVEL_TRIGGER, NULL);
}
#endif /* CONFIG_X86_32 */
static void mask_IO_APIC_irq_desc(struct irq_desc *desc)
{
@ -2510,11 +2508,8 @@ atomic_t irq_mis_count;
static void ack_apic_level(unsigned int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
#ifdef CONFIG_X86_32
unsigned long v;
int i;
#endif
struct irq_cfg *cfg;
int do_unmask_irq = 0;
@ -2527,31 +2522,28 @@ 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
*/
* 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
*/
cfg = desc->chip_data;
i = cfg->vector;
v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));
#endif
/*
* We must acknowledge the irq before we move it or the acknowledge will
@ -2593,7 +2585,7 @@ static void ack_apic_level(unsigned int irq)
unmask_IO_APIC_irq_desc(desc);
}
#ifdef CONFIG_X86_32
/* Tail end of version 0x11 I/O APIC bug workaround */
if (!(v & (1 << (i & 0x1f)))) {
atomic_inc(&irq_mis_count);
spin_lock(&ioapic_lock);
@ -2601,7 +2593,6 @@ static void ack_apic_level(unsigned int irq)
__unmask_and_level_IO_APIC_irq(cfg);
spin_unlock(&ioapic_lock);
}
#endif
}
#ifdef CONFIG_INTR_REMAP