Hi Stephen, On 25/03/2019 18:10, Stephen Boyd wrote: > This function returns an error if a child irqchip calls > irq_chip_set_wake_parent() but its parent irqchip has the > IRQCHIP_SKIP_SET_WAKE flag set. Let's return 0 for success here instead > because there isn't anything to do. > > This keeps the behavior consistent with how set_irq_wake_real() is > implemented. That function returns 0 when the irqchip has the > IRQCHIP_SKIP_SET_WAKE flag set. It doesn't attempt to walk the chain of > parents and set irq wake on any chips that don't have the flag set > either. If the intent is to call the .irq_set_wake() callback of the > parent irqchip, then we expect irqchip implementations to omit the > IRQCHIP_SKIP_SET_WAKE flag and implement an .irq_set_wake() function > that calls irq_chip_set_wake_parent(). > > This fixes a problem on my Qualcomm sdm845 device where I can't set wake > on any GPIO interrupts after I apply work in progress wakeup irq patches > to the GPIO driver. The chain of chips looks like this: > > ARM GIC (skip) -> QCOM PDC (skip) -> QCOM GPIO nit: the parenting chain is actually built the other way around (we don't express the 'child' relationship). This doesn't change anything to the patch, but would make the reasoning a but easier to understand. > > The GPIO controller is a child of the QCOM PDC irqchip which is a child > of the ARM GIC irqchip. The QCOM PDC irqchip has the > IRQCHIP_SKIP_SET_WAKE flag set, and so does the grandparent ARM GIC. > > The GPIO driver doesn't know if the parent needs to set wake or not, so > it unconditionally calls irq_chip_set_wake_parent() causing this > function to return a failure because the parent irqchip (PDC) doesn't > have the .irq_set_wake() callback set. Returning 0 instead makes > everything work and irqs from the GPIO controller can be configured for > wakeup. > > Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx> > Cc: Marc Zyngier <marc.zyngier@xxxxxxx> > Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx> Fixes: 08b55e2a9208e ("genirq: Add irqchip_set_wake_parent") Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx> Thanks, M. -- Jazz is not dead. It just smells funny...