The proposed device-specific command uses a mechanism originally made
for modules instead (more on that below).
I think we should make up our minds which way we want device-specific
commands done, then do *all* of them that way.
I think device specific commands make sense, but I think it would
probably be better if we had an 'info dev $name' and that a method on
the device rather than registering each one separately.
I'd assume that this would be a QMP level thing that got unwrapped at
HMP.
But that's not a problem for this contribution; someone else can figure
that out later.
Actually I think this would solve a problem with this contribution.
This patch implements a QMP command but never registers it, so it
isn't actually accessible via QMP. It only registers the HMP wrapper
which rather defeats the point of doing it via the QMP HumanReadableText
approach.
I'm guessing this was done because we don't have ability to dynamically
register QMP commands at runtime. I don't know how hard/easy it is
to address this, and perhaps we don't even want to. It was a problem
for me when previously converting HMP info commands to QMP and I
didn't get a solution, so didn't convert anything where the command
impl was dynamically registered at runtime. This basically excluded
converting devices that have been split into loadable modules.
If we had a general 'info dev-debug' (HMP) and 'x-query-dev-debug'
commands, then we could side-step the QMP limitation, as both thue
HMP and QMP comamnds could be statically registered. The devices
then only need to register a callback at runtime which should be
easier to deal with.