[PATCH] i386: irq: Kill IRQ compression

Len Brown
2007-02-16T05:16:30Z

This code makes simple systems complex:

ACPI: PCI Interrupt 0000:03:04.0[A] -> GSI 18 (level, low) -> IRQ 16
ACPI: PCI Interrupt 0000:00:1d.0[A] -> GSI 16 (level, low) -> IRQ 17
ACPI: PCI Interrupt 0000:00:1d.1[B] -> GSI 19 (level, low) -> IRQ 18
ACPI: PCI Interrupt 0000:00:1d.7[D] -> GSI 23 (level, low) -> IRQ 19

The same code was already removed from x86_64

Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Natalie Protasevich <Natalie.Protasevich@UNISYS.com>
---
arch/i386/kernel/io_apic.c | 5 ----
arch/i386/kernel/mpparse.c | 41 ---------------------------------
include/asm-i386/io_apic.h | 1
3 files changed, 1 insertion(+), 46 deletions(-)

Index: linus/arch/i386/kernel/mpparse.c
===================================================================
--- linus.orig/arch/i386/kernel/mpparse.c
+++ linus/arch/i386/kernel/mpparse.c
@@ -1041,20 +1041,12 @@ void __init mp_config_acpi_legacy_irqs (
}
}

-#define MAX_GSI_NUM 4096
-
int mp_register_gsi(u32 gsi, int triggering, int polarity)
{
int ioapic = -1;
int ioapic_pin = 0;
int idx, bit = 0;
static int pci_irq = 16;
- /*
- * Mapping between Global System Interrups, which
- * represent all possible interrupts, and IRQs
- * assigned to actual devices.
- */
- static int gsi_to_irq[MAX_GSI_NUM];

/* Don't set up the ACPI SCI because it's already set up */
if (acpi_gbl_FADT.sci_interrupt == gsi)
@@ -1087,42 +1079,11 @@ int mp_register_gsi(u32 gsi, int trigger
if ((1<<bit) & mp_ioapic_routing[ioapic].pin_programmed[idx]) {
Dprintk(KERN_DEBUG "Pin %d-%d already programmed\n",
mp_ioapic_routing[ioapic].apic_id, ioapic_pin);
- return gsi_to_irq[gsi];
+ return gsi;
}

mp_ioapic_routing[ioapic].pin_programmed[idx] |= (1<<bit);

- if (triggering == ACPI_LEVEL_SENSITIVE) {
- /*
- * For PCI devices assign IRQs in order, avoiding gaps
- * due to unused I/O APIC pins.
- */
- int irq = gsi;
- if (gsi < MAX_GSI_NUM) {
- /*
- * Retain the VIA chipset work-around (gsi > 15), but
- * avoid a problem where the 8254 timer (IRQ0) is setup
- * via an override (so it's not on pin 0 of the ioapic),
- * and at the same time, the pin 0 interrupt is a PCI
- * type. The gsi > 15 test could cause these two pins
- * to be shared as IRQ0, and they are not shareable.
- * So test for this condition, and if necessary, avoid
- * the pin collision.
- */
- if (gsi > 15 || (gsi == 0 && !timer_uses_ioapic_pin_0))
- gsi = pci_irq++;
- /*
- * Don't assign IRQ used by ACPI SCI
- */
- if (gsi == acpi_gbl_FADT.sci_interrupt)
- gsi = pci_irq++;
- gsi_to_irq[irq] = gsi;
- } else {
- printk(KERN_ERR "GSI %u is too high\n", gsi);
- return gsi;
- }
- }
-
io_apic_set_pci_routing(ioapic, ioapic_pin, gsi,
triggering == ACPI_EDGE_SENSITIVE ? 0 : 1,
polarity == ACPI_ACTIVE_HIGH ? 0 : 1);
Index: linus/arch/i386/kernel/io_apic.c
===================================================================
--- linus.orig/arch/i386/kernel/io_apic.c
+++ linus/arch/i386/kernel/io_apic.c
@@ -2212,8 +2212,6 @@ static inline void unlock_ExtINT_logic(v
ioapic_write_entry(apic, pin, entry0);
}

-int timer_uses_ioapic_pin_0;
-
/*
* This code may look a bit paranoid, but it's supposed to cooperate with
* a wide range of boards and BIOS bugs. Fortunately only the timer IRQ
@@ -2250,9 +2248,6 @@ static inline void __init check_timer(vo
pin2 = ioapic_i8259.pin;
apic2 = ioapic_i8259.apic;

- if (pin1 == 0)
- timer_uses_ioapic_pin_0 = 1;
-
printk(KERN_INFO "..TIMER: vector=0x%02X apic1=%d pin1=%d apic2=%d pin2=%d\n",
vector, apic1, pin1, apic2, pin2);

Index: linus/include/asm-i386/io_apic.h
===================================================================
--- linus.orig/include/asm-i386/io_apic.h
+++ linus/include/asm-i386/io_apic.h
@@ -142,7 +142,6 @@ extern int io_apic_get_unique_id (int io
extern int io_apic_get_version (int ioapic);
extern int io_apic_get_redir_entries (int ioapic);
extern int io_apic_set_pci_routing (int ioapic, int pin, int irq, int edge_level, int active_high_low);
-extern int timer_uses_ioapic_pin_0;
#endif /* CONFIG_ACPI */

extern int (*ioapic_renumber_irq)(int ioapic, int irq);