1 files changed, 8 insertions, 3 deletions

diff --git a/arch/x86/kernel/mpparse_32.c b/arch/x86/kernel/mpparse_32.c
index 22fc8d7dec11..bfcfc41f5607 100644
--- a/arch/x86/kernel/mpparse_32.c
+++ b/arch/x86/kernel/mpparse_32.c
@@ -1041,13 +1041,14 @@ void __init mp_config_acpi_legacy_irqs (void)
 }
 
 #define MAX_GSI_NUM     4096
+#define IRQ_COMPRESSION_START   64
 
 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;
+        static int pci_irq = IRQ_COMPRESSION_START;
         /*
          * Mapping between Global System Interrups, which
          * represent all possible interrupts, and IRQs
@@ -1086,12 +1087,16 @@ int mp_register_gsi(u32 gsi, int triggering, int polarity)
         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 < IRQ_COMPRESSION_START ? gsi : gsi_to_irq[gsi]);
         }
 
         mp_ioapic_routing[ioapic].pin_programmed[idx] |= (1<<bit);
 
-        if (triggering == ACPI_LEVEL_SENSITIVE) {
+        /*
+         * For GSI >= 64, use IRQ compression
+         */
+        if ((gsi >= IRQ_COMPRESSION_START)
+                && (triggering == ACPI_LEVEL_SENSITIVE)) {
                 /*
                  * For PCI devices assign IRQs in order, avoiding gaps
                  * due to unused I/O APIC pins.