[PATCH v4 16/24] xen: clear IRQ_NOAUTOEN and IRQ_NOREQUEST

On 14/09/12 15:28, Stefano Stabellini wrote:

On Fri, 14 Sep 2012, Marc Zyngier wrote:

quoted

On 14/09/12 15:13, Stefano Stabellini wrote:

quoted

On Fri, 14 Sep 2012, Marc Zyngier wrote:

quoted

On 14/09/12 12:13, Stefano Stabellini wrote:

quoted

Reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by
default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call
irq_startup, that is responsible for calling irq_unmask at startup time.
As a result event channels remain masked.

Signed-off-by: Stefano Stabellini <redacted>
Acked-by: Konrad Rzeszutek Wilk <redacted>
---
 drivers/xen/events.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 5ecb596..8ffb7b7 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c

@@ -836,6 +836,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 		struct irq_info *info = info_for_irq(irq);
 		WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
 	}
+	irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);

This one just sent a shiver down my spine. Are you doing this for a PPI?

Not really: even though there is just one source of event notifications
(that is a PPI), we have many event channels. When a domain receives a
notification (via the PPI), it checks on a bitmask to which event channel
it corresponds. From the Linux point of view every event channel is a
Linux irq belonging to the xen_dynamic_chip (see
drivers/xen/events.c:xen_dynamic_chip).

So here I am not doing this for the one PPI, but I am doing this for
every Linux irq (of chip xen_dynamic_chip) that represents an event
channel.

So this is some sort of secondary interrupt controller, cascaded into
your GIC emulation,

    
I guess it could be seen as a secondary interrupt controller

quoted

and this patch only affects the xen_dynamic_chip?

Yep

Thanks. I feel relieved... ;-)

	M.
-- 
Jazz is not dead. It just smells funny...