x86: 32-bit IOAPIC: de-fang IRQ compression
[sfrench/cifs-2.6.git] / arch / x86 / kernel / mpparse_32.c
index 22fc8d7dec1130331d6af172eafc29acbbbdeefb..bfcfc41f56070d1a06582e0c4cbbc7e61ab5c194 100644 (file)
@@ -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.