msg: VehicleCommandAck: bump queue length from 4 to 8

[dakejahl]

Increase VehicleCommandAck ORB_QUEUE_LENGTH to match VehicleCommand
https://discord.com/channels/1022170275984457759/1022185721450213396/1456709818474828079

[julianoes]

I have a dejavu that I wanted to do this as well at some point.

[julianoes]

Ignoring unrelated CI.

[DonLakeFlyer]

So with equal side queue on both ends does this mean I'll get command failures when the queue is full as opposed to lost acks? If the command fails for this case is there anyway to know it's because of this queue full on the QGC side of things?

[dakejahl]

So with equal side queue on both ends does this mean I'll get command failures when the queue is full as opposed to lost acks? If the command fails for this case is there anyway to know it's because of this queue full on the QGC side of things?

I don't think publication of the command fails. I believe uORB will always publish and the queue will quietly overflow. Ideally we would have a mechanism to prevent that, and have publish() fail if the queue is full.

[DonLakeFlyer]

Ideally we would have a mechanism to prevent that, and have publish() fail if the queue is full.

yeah, that's kinda nasty behavior