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| author | David Gibson <david@gibson.dropbear.id.au> | 2007-08-14 13:52:42 +1000 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2007-08-17 11:02:06 +1000 |
| commit | 553fdff633b1cb8cfccf554768444c5580a8d7f7 (patch) | |
| tree | 6d87847e2ee77bb60ada7c3dee2158af93352a7b /arch/powerpc/sysdev/uic.c | |
| parent | 868afce21fdadcecc7bde9263321065948508c56 (diff) | |
| download | linux-stable-553fdff633b1cb8cfccf554768444c5580a8d7f7.tar.gz linux-stable-553fdff633b1cb8cfccf554768444c5580a8d7f7.tar.bz2 linux-stable-553fdff633b1cb8cfccf554768444c5580a8d7f7.zip | |
[POWERPC] Improve robustness of the UIC cascade handler
At present the cascade interrupt handler for the UIC (interrupt
controller on 4xx embedded chips) will misbehave badly if it is called
spuriously - that is if the handler is invoked when no interrupts are
asserted in the child UIC.
Although spurious interrupts shouldn't happen, it's good to behave
robustly if they do. This patch does so by checking for and ignoring
spurious interrupts.
Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/sysdev/uic.c')
| -rw-r--r-- | arch/powerpc/sysdev/uic.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/uic.c b/arch/powerpc/sysdev/uic.c index 22c219e448d4..47180b3fca56 100644 --- a/arch/powerpc/sysdev/uic.c +++ b/arch/powerpc/sysdev/uic.c @@ -266,6 +266,9 @@ irqreturn_t uic_cascade(int virq, void *data) int subvirq; msr = mfdcr(uic->dcrbase + UIC_MSR); + if (!msr) /* spurious interrupt */ + return IRQ_HANDLED; + src = 32 - ffs(msr); subvirq = irq_linear_revmap(uic->irqhost, src); |