| Message ID | 20140702034811.2956.30873.stgit@preeti.in.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Wed, 2014-07-02 at 09:19 +0530, Preeti U Murthy wrote: > Commit 8d6f7c5a: "powerpc/powernv: Make it possible to skip the IRQHAPPENED > check in power7_nap()" added code that prevents cpus from checking for > pending interrupts just before entering sleep state, which is wrong. These > interrupts are delivered during the soft irq disabled state of the cpu. Acked-by: Michael Ellerman <mpe@ellerman.id.au> cheers
diff --git a/arch/powerpc/kernel/idle_power7.S b/arch/powerpc/kernel/idle_power7.S index 2480256..5cf3d36 100644 --- a/arch/powerpc/kernel/idle_power7.S +++ b/arch/powerpc/kernel/idle_power7.S @@ -131,7 +131,7 @@ _GLOBAL(power7_nap) _GLOBAL(power7_sleep) li r3,1 - li r4,0 + li r4,1 b power7_powersave_common /* No return */
Commit 8d6f7c5a: "powerpc/powernv: Make it possible to skip the IRQHAPPENED check in power7_nap()" added code that prevents cpus from checking for pending interrupts just before entering sleep state, which is wrong. These interrupts are delivered during the soft irq disabled state of the cpu. A cpu cannot enter any idle state with pending interrupts because they will never be serviced until the next time the cpu is woken up by some other interrupt. Its only then that the pending interrupts are replayed. This can result in device timeouts or warnings about this cpu being stuck. This patch fixes ths issue by ensuring that cpus check for pending interrupts just before entering any idle state as long as they are not in the path of split core operations. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> --- Chanes in V2: https://lkml.org/lkml/2014/7/1/3 Modified the changelog to add the details of the problem that this patch fixes Changes in V3: V2 assumed that this patch would be useful only in the context of doorbell ipis. But that is not true; this patch is required to correctly handle any type of interrupt delivered in the idle enter path. arch/powerpc/kernel/idle_power7.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)