The CCP has the ability to perform several operations simultaneously,
but only one interrupt. When implemented as a PCI device and using
MSI-X/MSI interrupts, use a tasklet model to service interrupts. By
disabling and enabling interrupts from the CCP, coupled with the
queuing that tasklets provide, we can ensure that all events
(occurring on the device) are recognized and serviced.
This change fixes a problem wherein 2 or more busy queues can cause
notification bits to change state while a (CCP) interrupt is being
serviced, but after the queue state has been evaluated. This results
in the event being 'lost' and the queue hanging, waiting to be
serviced. Since the status bits are never fully de-asserted, the
CCP never generates another interrupt (all bits zero -> one or more
bits one), and no further CCP operations will be executed.
Cc: <stable@vger.kernel.org> # 4.9.x+
Signed-off-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
6263b51eb3