Index: linux-2.6.33.2/arch/mips/kernel/traps.c =================================================================== --- linux-2.6.33.2.orig/arch/mips/kernel/traps.c 2010-04-02 01:02:33.000000000 +0200 +++ linux-2.6.33.2/arch/mips/kernel/traps.c 2010-04-02 23:36:16.000000000 +0200 @@ -1496,7 +1496,18 @@ if (cpu_has_mips_r2) { cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP; cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7; + + if (!cp0_compare_irq) + cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ; + cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7; + + if (!cp0_perfcount_irq) + cp0_perfcount_irq = CP0_LEGACY_PERFCNT_IRQ; + + if (arch_fixup_c0_irqs) + arch_fixup_c0_irqs(); + if (cp0_perfcount_irq == cp0_compare_irq) cp0_perfcount_irq = -1; } else { Index: linux-2.6.33.2/arch/mips/include/asm/irq.h =================================================================== --- linux-2.6.33.2.orig/arch/mips/include/asm/irq.h 2010-04-02 01:02:33.000000000 +0200 +++ linux-2.6.33.2/arch/mips/include/asm/irq.h 2010-04-02 23:37:14.000000000 +0200 @@ -133,9 +133,11 @@ * IE7. Since R2 their number has to be read from the c0_intctl register. */ #define CP0_LEGACY_COMPARE_IRQ 7 +#define CP0_LEGACY_PERFCNT_IRQ 7 extern int cp0_compare_irq; extern int cp0_compare_irq_shift; extern int cp0_perfcount_irq; +extern void __weak arch_fixup_c0_irqs(void); #endif /* _ASM_IRQ_H */