Question regarding VIRTIO_RING_F_EVENT_IDX

Hi,

In Section 2.4.5, "The Virtqueue Available Ring", it says:

> If the VIRTIO_RING_F_INDIRECT_DESC feature bit is not negotiated, the “flags” field offers a crude interrupt
> control mechanism. The driver MUST set this to 0 or 1: 1 indicates that the device SHOULD NOT
> send an interrupt when it consumes a descriptor chain from the available ring. The device MUST ignore the
> used_event value in this case.

Shouldn't it be VIRTIO_RING_F_EVENT_IDX instead of
VIRTIO_RING_F_INDIRECT_DESC?
The next paragraph says:

> Otherwise, if the VIRTIO_RING_F_EVENT_IDX feature bit is negotiated, the driver MUST set the "flags" field
> to 0, and use the “used_event” field in the used ring instead. The driver can ask the device to delay interrupts
> until an entry with an index specified by the “used_event” field is written in the used ring (equivalently, until
> the idx field in the used ring will reach the value used_event + 1).

The same question also applies to Section 2.4.6.

Thanks,
Haggai