This fix is a backport from the reworked nouveau driver. It masks off the
engines we're not expecting to use before attempting a channel kickoff.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Been tested on each major revision that's relevant here, but I'm sure there
are still bugs waiting to be ironed out.
This is a *very* invasive change.
There's a couple of pieces left that I don't like much (eg. other engines
using fifo_priv for the channel count), but that's an artefact of there
being a master channel list still. This is changing, slowly.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
