On Tue, 2018-06-19 at 16:51 -0500, Jonathon Jongsma wrote:
> On Tue, 2018-06-19 at 15:15 +0200, Lukáš Hrázký wrote:
> > On Tue, 2018-06-19 at 08:11 -0400, Frediano Ziglio wrote:
> > > >
> > > > On Fri, 2018-06-15 at 15:12 +0200, Marc-André Lureau wrote:
> > > > > Hi
> > > > >
> > > > > On Fri, Jun 15, 2018 at 1:01 PM, Lukáš Hrázký <lhrazky@redhat.c
> > > > > om> wrote:
> > > > > > On Fri, 2018-06-15 at 12:24 +0200, Marc-André Lureau wrote:
> > > > > > > Hi
> > > > > > >
> > > > > > > On Fri, Jun 15, 2018 at 12:16 PM, Lukáš Hrázký <lhrazky@red
> > > > > > > hat.com>
> > > > > > > wrote:
> > > > > > > > On Thu, 2018-06-14 at 21:12 +0200, Marc-André Lureau
> > > > > > > > wrote:
> > > > > > > > > Hi
> > > > > > > > >
> > > > > > > > > On Tue, Jun 5, 2018 at 5:30 PM, Lukáš Hrázký <lhrazky@r
> > > > > > > > > edhat.com>
> > > > > > > > > wrote:
> > > > > > > > > > Hi everyone,
> > > > > > > > > >
> > > > > > > > > > following is my attempt at solving the ID issues with
> > > > > > > > > > monitors_config
> > > > > > > > > > and streaming. The concept is as follows:
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > Before introducing a new solution, could you describe
> > > > > > > > > the "issues
> > > > > > > > > with
> > > > > > > > > monitors_config and streaming"? I am not following
> > > > > > > > > closely enough
> > > > > > > > > the
> > > > > > > > > mailing list probably, so a recap would be welcome. I'd
> > > > > > > > > like to
> > > > > > > > > understand the shortcomings of the current messages,
> > > > > > > > > and see if we
> > > > > > > > > are
> > > > > > > > > on the same page about it. Thanks!
> > > > > > > >
> > > > > > > > Right, sorry about that!
> > > > > > > >
> > > > > > > > The issue is when having a plugin a for the streaming
> > > > > > > > agent that is
> > > > > > > > using a HW-accelerated encoder. The typical case is that
> > > > > > > > you have a
> > > > > > > > QXL
> > > > > > > > monitor in the guest which shows the boot and then you
> > > > > > > > have a
> > > > > > > > physical
> > > > > > > > HW device (either directly assigned to the VM or a vGPU)
> > > > > > > > which is
> > > > > > > > configured in the X server.
> > > > > > > >
> > > > > > > > Once the X server starts, the QXL monitor goes blank and
> > > > > > > > you get a
> > > > > > > > second monitor on the client with the streamed content
> > > > > > > > from the
> > > > > > > > streaming agent plugin.
> > > > > > > >
> > > > > > > > The problem is the code and the protocol assumes (amongst
> > > > > > > > other
> > > > > > > > assumptions) that all monitors are configured in X. The
> > > > > > > > monitors on
> > > > > > > > the
> > > > > > > > client are put into an array and the index is used as the
> > > > > > > > ID
> > > > > > > > throughout
> > > > > > > > SPICE. So for the case above, the QXL monitor is ID 0 and
> > > > > > > > the
> > > > > > > > streamed
> > > > > > > > monitor is ID 1.
> > > > > > >
> > > > > > >
> > > > > > > Since the "streamed monitor" replaces the QXL monitor,
> > > > > > > wouldn't it
> > > > > > > make sense for them to share the same ID? This would be
> > > > > > > handled by the
> > > > > > > server/guest transparently.
> > > > > >
> > > > > > Well... for one, it does not entirely replace it. From a user
> > > > > > experience PoV, yes, it makes sense to "replace" one monitor
> > > > > > for the
> > > > > > other. We've even considered switching the content of the
> > > > > > display
> > > > > > channel from QXL to the streamed one. But in the system, they
> > > > > > are
> > > > > > different monitors on different channels, so it's a bad idea
> > > > > > to give
> > > > > > them the same ID. And the ID we're talking about is actually
> > > > > > (for the
> > > > > > monitors config messages):
> > > > >
> > > > > So if it's the same from use PoV, the client API shouldn't need
> > > > > to change.
> > > >
> > > > I didn't say it's the same from the user PoV, not entirely. We
> > > > can
> > > > assume he want's to either be looking at the QXL monitor or the
> > > > streamed one, i.e.:
> > > >
> > > > 1. VM is booting, we are showing QXL monitor
> > > > 2. X started, we switch to showing the streamed monitor
> > >
> > > Note: this is also due to X limitation not supporting multiple
> > > devices,
> > > on Windows probably you'll have both used at the same time and
> > > probably
> > > user will manually disable QXL (as wants to use the other)
> > >
> > > > 3. The user switches to a different TTY, we switch back to QXL
> > > > etc...
> > > >
> > > > This is for the simple case of one QXL monitor and one streamed
> > > > monitor. But we are still "hiding" from the user that his VM
> > > > actually
> > > > has two graphics devices, the QXL one and a physical (or virtual)
> > > > GPU.
> > > >
> > > > I once advocated the approach to switch the monitors for the
> > > > users, but
> > > > now I think it would actually complicate things more and could
> > > > potentially cause problems.
> > > >
> > >
> > > I think the possibility to have the switch would be interesting and
> > > help
> > > but I think the actual protocol is limiting and potentially
> > > complicating
> > > stuff.
> > >
> > > > > The client only cares about about having a specific set of
> > > > > monitors
> > > > > configuration. The way the server/guest handled them is not its
> > > > > business, it expects the best configuration.
> > >
> > > True, the client should implement the protocol and server should
> > > use
> > > the protocol as best as it can. This does not however mean that the
> > > current protocol is perfect and using it as it is don't limit us
> > > and make the code a bunch of spaghetti code in order to make
> > > protocol
> > > happy.
> >
> > Actually, I've realized this is an interesting point by Marc-André,
> > the
> > client doesn't neccessarily need to care for the output_id I've added
> > to the protocol.
> >
> > There was a suggestion by Uri to keep the output_id in a map on the
> > server and not send it to the client and back. That would mean no
> > protocol change. However, it is not possible because of the ID
> > discrepancy. There is no reliable key to use in the server on both
> > the
> > sending and the receiving side.
> >
> > It might be an idea to just fix the IDs in the protocol and still use
> > the map instead of sending the output_id through the client.
>
>
> So, I think we mostly agree that the protocol design in this area is
> not ideal. On the other hand, if we can make it work without any
> protocol changes, it makes for a far less complicated transition (no
> capabilities flags, no handling of old and new protocol messages, etc).
> So if we can make things work without changes to the protocol, that
> would be nice.
>
> Your current approach is that the guest sends a message to the server
> to tell the server the output_id associated with a given stream. Then
> this output_id is passed on to the client so that the client can pass
> it back to the server, who then passes it on to the guest.
>
> What if, instead, we switch the responsibilities around?
>
> What if we made the server tell the guest which ID it associates with
> the stream (instead of the guest telling the server). The ID that the
> server assigns to the stream would just be the channel ID + monitor ID
> to match the client's assumptions. Then the guest agent would maintain
> a map from server ID to xrandr ID. That would perhaps allow us to avoid
> changing the protocol messages. Of course, maybe you already considered
> this approach and there's a reason that it won't work that I'm not
> considering.
The issue with this is that in the guest there are two agents. The
streaming agent and the vd_agent. So the server can tell the streaming
agent which ID it assigned to the stream, and the streaming agent would
maintain that map, but it's in the vd_agent where you'd need look up
the xrandr ID in the map. So this doesn't really work.
It also spreads the channel_id + monitor_id hack into the server,
digging us a deeper hole :) I believe we can't get rid of that without
protocol changes (and if Frediano's story is correct, it was introduced
to avoid protocol changes too).
Cheers,
Lukas
> Jonathon
>
> >
> > > > That is true, but the monitors configuration needs to reflect the
> > > > actual configuration of the guest. If we mix it up for the
> > > > clients
> > > > convenience, problems... :)
> > > >
> > > > > So far, we have the current simplified model (ie other more
> > > > > complex
> > > > > combinations are not supported):
> > > > >
> > > > > qxl device, display channel 0,
> > > > > monitor 0:
> > > > > monitor 1:
> > > > > monitor x..
> > > > >
> > > > >
> > > > > or
> > > > >
> > > > > qxl device, display channel 0,
> > > > > monitor 0:
> > > > > qxl device, display channel 1,
> > > > > monitor 0:
> > > > > ..
> > > > >
> > > > > Feel free to correct me, I haven't been looking into this for
> > > > > many years
> > > > > now.
> > > >
> > > > Correct.
> > > >
> > >
> > > True. Note that this model however have physical (sockets and
> > > connections)
> > > repercussions which could be hard to maintain.
> > > If we decide to keep the current protocol and have one device we
> > > end up
> > > with a huge surface 0 with all monitors in it having to mux and
> > > unmux streamings
> > > and commands in both server and clients having to implement fair
> > > queueing and
> > > synchronization just to maintain an old design.
> > > Said that this approach would be prohibitive and looking at X
> > > implementation
> > > requiring a single surface this means that if streaming devices are
> > > used we must
> > > limit to one QXL with 1 monitor only and "map" all monitors to
> > > different channels
> > > (with one monitor each).
> >
> > Tbh. I'm kind of lost here, I think this branch of the discussion is
> > mostly irrelevant, in case it's not, please let me know.
> >
> > > > > >
> > > > > > server -> client: a pair (channel_id, monitor_id)
> > > > > >
> > > > > > client -> server: channel_id + monitor_id, converted to an
> > > > > > array index
> > > > > > under the assumption I mentioned
> > > > > >
> > > > > > So we can't really make it the same even if we wanted.
> > > > >
> > > > > With multi-head/xrandr qxl:
> > > > >
> > > > > qxl device, display channel 0,
> > > > > monitor 0:
> > > > > monitor 1:
> > > > > monitor x..
> > > > > gpu device, stream channel 0,
> > > > > maps to display channel 0, monitor 0
> > > > > gpu device, stream channel 1,
> > > > > maps to display channel 0, monitor 1
> > > > > ...
> > > > >
> > > > > With multihead/xrandr qxl & gpu:
> > > > > qxl device, display channel 0,
> > > > > monitor 0:
> > > > > monitor 1:
> > > > > monitor x..
> > > > > gpu device, stream channel 0,
> > > > > maps to display channel 0, monitor 0
> > > > > maps to display channel 0, monitor 1
> > > > > ...
> > > > >
> > > > > With multiple QXL devices:
> > > > >
> > > > > qxl device, display channel 0,
> > > > > monitor 0:
> > > > > qxl device, display channel 1,
> > > > > monitor 0:
> > > > > gpu device, stream channel 0,
> > > > > maps to display channel 0, monitor 0
> > > > > gpu device, stream channel 1,
> > > > > maps to display channel 1, monitor 0
> > > >
> > > > But, regardless of multihead/multiple devices, there is no
> > > > guarantee
> > > > that the number of QXL monitors is going to match the number of
> > > > GPU
> > > > device monitors. In fact, the most probable scenario is one QXL
> > > > monitor
> > > > and multiple GPU device monitors.
> > > >
> > >
> > > This is not an issue, would be just a problem of allocating enough
> > > channels to support all monitors we need.
> > >
> > > > I don't think it makes sense to have more than one QXL monitor
> > > > anyway.
> > > > And if you did, it makes no sense to map them to GPU device
> > > > monitors
> > > > besides the first one, I guess...
> > > >
> > > > Also, it is unclear what you mean by the "mapping", i.e. how
> > > > exactly
> > > > would you implement it?
> > > >
> > >
> > > Simply to the client you present a channel_id, monitor_id which can
> > > be different on the server.
> >
> > The hair on my neck is rising when I'm just thinking of this :D
> >
> > (Don't mess with the IDs!)
> >
> > > > > If you want to support QXL devices that should not be
> > > > > associated with
> > > > > a gpu/stream channel, then you should be able to flag them.
> > >
> > > Not clear what do you want with this. A QXL device should be either
> > > be
> > > seen by the client or not. You need to flag if seen or not.
> > >
> > > > >
> > > > > If you need a manual association of stream channel with
> > > > > qxl/monitor,
> > > > > this could be done with a manual configuration.
> > >
> > > I don't see a case where I would need a manual configuration, I
> > > mean,
> > > should be configurable within the guest disabling/enabling devices
> > > and/or monitors.
> > >
> > > > >
> > > > > Imho, we should avoid making things more complex. Testing is
> > > > > hard
> > > > > enough. We should actually take the simplest approach possible
> > > > > (the
> > > > > same decision we took before, it's already a mess to deal with,
> > > > > as you
> > > > > noticed)
> > >
> > > You are stating that the current situation is complex and also we
> > > need
> > > to keep things simple. Looks like a bit contradictory.
> > > Maybe the current situation is complex, or feel more complex than
> > > it
> > > should be, for the choices done and current implementation.
> > > From my point of view is just that client need to tell "I want this
> > > monitor this size" and "I'm moving the mouse here on this monitor".
> > > The problem is defining "this monitor" at protocol level from
> > > client
> > > to server, including messages to agent.
> > >
> > > >
> > > > I fully agree with the notion :) However, we are already making
> > > > things
> > > > much more complex by adding the GPU device streaming feature. It
> > > > breaks
> > >
> > > I don't think the problem is related to streaming, more about
> > > devices
> > > which are not QXL. With only QXL all old assumptions are easy to
> > > maintain,
> > > the problem is the new devices. For instance having QXL 0 as Xrandr
> > > ID 0
> > > and QXL 1 as Xrandr ID 1 is pretty easy, is the same driver and
> > > actually
> > > we also manage (at code level!) the guest device driver. Just
> > > imagine if
> > > the driver changes the order or physical device scanning having QXL
> > > 0 as
> > > Xrandr 1 and QXL 1 as Xrandr 0! This would break the
> > > channel_id+monitor_id
> > > formula. This does not happen as we maintain it, but we (SPICE)
> > > don't
> > > maintain Intel/Nvidia/ATI drivers or Xorg/Wayland/Windows!
> >
> > Yeah, this, though it doesn't seem likely, is something we should be
> > aware of. It doesn't break my current implementation though, because
> > (AFAICS it's going to be implemented in multi-monitor support for
> > stremaing) the streaming agent gets the IDs from xrandr and in the
> > end
> > the IDs will again be used with xrandr, so as long as we keep them
> > updated, the IDs will match.
> >
> > > I'm relative new in this group (3 years) compared to these stuff,
> > > some are possibly not in current git repos, but I think that more
> > > or
> > > less the history is:
> > > - before multimonitor. No much issues the monitor was the monitor;
> > > - start adding multi monitor support, only one device was used. The
> > > problem was only sending the ID of the monitor which was 0, 1,
> > > ...
> > > Added a monitor_config message in the SPICE protocol from server
> > > to client. The client could resize the monitors sending a message
> > > to the agent through the server, server was not involved. As
> > > there
> > > was only a QXL device and no other devices there was no reason to
> > > send
> > > information for channel/qxl device and monitor IDs matched Xrandr
> > > IDs;
> > > - for some reasons on Windows was not great, somebody decided to
> > > use
> > > multiple QXL devices each with one monitor. As a workaround not
> > > having
> > > the channel in the protocol to the agent the
> > > channel_id+monitor_id formula
> > > was introduced to create an ID fitting into the existing one (for
> > > the
> > > agent);
> > > - somebody realized that on Linux was possible to handle resolution
> > > changes talking directly to the device making possible resize
> > > without
> > > using the agent. This was implemented with a change in device
> > > modes
> > > (rom/ram) and an interrupt to the card handled by our Linux
> > > kernel
> > > driver. As on Linux there is only one device, spice-server just
> > > "redirects" the message for the agent sent by the client to the
> > > QXL
> > > card. This works on Windows as Windows driver does not handle
> > > this
> > > interrupt/feature (or it would replicate monitor settings on all
> > > cards!).
> > > Possibly some wrong assumptions, please correct me.
> > > Note: is not clear to me the history of the mouse events, currently
> > > spice-server sends messages to the agent for the mouse.
> > >
> > > > previous assumptions and adds more stuff on top of it. And I
> > > > think your
> > > > suggestion adds even more complexity than necessary. Perhaps not
> > > > in the
> > > > client, but the "mapping" code, which sounds rather non-trivial,
> > > > needs
> > > > to go somewhere, presumably the server?
> > > >
> > >
> > > I think too that bending to the old "design" will do stuff more
> > > complex.
> > >
> > > > It is actually my intention to add as little complexity as
> > > > possible
> > > > with my patches. The fact is, both the current code and the
> > > > protocol is
> > > > not robust enough and need to be fixed. And even if they were
> > > > robust
> > >
> > > I would not speak about robustness and fix, from my point of view
> > > looks
> > > more a problem of flexibility. Simply we now have new use cases to
> > > support.
> >
> > Yeah, that's mostly what I meant to say.
> >
> > > > enough, the protocol would need to be extended either way. On top
> > > > of
> > > > that, the backwards compatibility turns the solution into a very
> > > > complex one. But if we ever could deprecate and drop the old code
> > > > paths...
> > > >
> > >
> > > I have same sensation, not changing protocol will make thing much
> > > more complicated and possibly limited.
> > >
> > > > > > > > The more pressing issue with this is that a mouse motion
> > > > > > > > event is
> > > > > > > > sent
> > > > > > > > with a display_id 1 from the client, but when it reaches
> > > > > > > > the guest,
> > > > > > > > the
> > > > > > > > correct monitor is ID 0, as it is the only one.
> > > > > > > >
> > > > > > > > The other thing this breaks is monitors_config messages
> > > > > > > > that
> > > > > > > > enable/disable displays and change the resolution.
> > > > > > > > Besides the same
> > > > > > > > "shift" happening here as well, another problem is the
> > > > > > > > information
> > > > > > > > that
> > > > > > > > the monitors belong to different devices (or channels) is
> > > > > > > > erased when
> > > > > > > > they're all put into the single array (under the
> > > > > > > > assumption there is
> > > > > > > > either one channel with multiple monitors or multiple
> > > > > > > > channels with
> > > > > > > > one
> > > > > > > > monitor each).
> > > > > > >
> > > > > > > Correct and so far was a fine solution.
> > > > > >
> > > > > > I respectfully disagree. Doing the channel_id + monitor_id I
> > > > > > mentioned
> > > > > > above is asking for trouble, which is exactly what we have
> > > > > > now.
> > > > >
> > > > > With the limitation we decided, we avoid the biggest troubles
> > > > > though.
> > >
> > > We avoid to change the protocol but to implement the new use cases
> > > we introduce potentially many assumptions and code complexity.
> > > Not saying that is hard to discuss new code thinking about design
> > > which nobody wrote down and that is bound to old code which nobody
> > > fully remember.
> > >
> > > >
> > > > I take it you were involved with the original implementation
> > > > then...
> > > > I'm sorry for being so critical, it is not my intention to be
> > > > mean :)
> > > >
> > > > However, I am not criticising the limitations you chose to
> > > > impose, but
> > > > the implementation. I find two problems here:
> > > >
> > > > 1. Not keeping the IDs of the monitors_config messages as a
> > > > (channel_id, monitor_id) pair and instead abusing the limitation
> > > > you
> > > > introduced to change it to a singe ID. I sort of consider it a
> > > > hard
> > > > rule you always keep your unique IDs intact and always keep them
> > > > with
> > > > the data. That way they're there when you need them and they work
> > > > (because you didn't mess with them :)).
> > > >
> > >
> > > I think this single ID came from the history I wrote above (that
> > > could
> > > be partly wrong).
> >
> > Indeed, I haven't realized that possible sequence of events. In that
> > case it kind of proves the point that when you take shortcuts to make
> > things easier, you're just digging yourself a hole...
> >
> > > I personally would add channel_id and monitor_id to the new
> > > messages,
> > > this to make possible to send the correct modes to the card in
> > > every
> > > possible case. Saving few bytes for these messages (which are not
> > > that frequent) is not worth it.
> >
> > Yes, I've already decided to do that in the next iteration.
> >
> > > > 2. The change in the IDs and the actual creation of the
> > > > monitors_config
> > > > list leaks over the spice-gtk API to the client application (via
> > > > the
> > > > spice_main_update_display{,_enabled}() function). It is
> > > > unnecessary,
> > > > gives more opportunity to the client app to break it, and any
> > > > extension
> > > > of the monitors_config message requires a spice-gtk API change.
> > > >
> > > > You could have imposed the limitation you did (I'm not entirely
> > > > sure
> > > > what was the reason) and still make the implementation more
> > > > robust by
> > > > not doing the above...
> > > >
> > > > And for these reasons this patch series is more complicated that
> > > > it
> > > > could have been (though as I said, the protocol extension, i.e.
> > > > adding
> > > > the output_id) would still be necessary.
> > > >
> > > > I'm not saying this to pick on you, I'm not even sure how you
> > > > were
> > > > involved (didn't go digging who wrote the code), but more as an
> > > > explanation and so that we all can learn from it for the future
> > > > :)
> > > >
> > >
> > > Usually complex code is the result of many passages and possibly
> > > shortcuts, usually involving different people and undocumented
> > > stuff. Picking on people is often unfair.
> > >
> > > > > > > Either you do multiple monitor over a single channel, or
> > > > > > > you use
> > > > > > > multiple
> > > > > > > channels, each with one monitor.
> > > > > >
> > > > > > That is a limitation you can introduce, perhaps there was a
> > > > > > reason for
> > > > > > it. But the code is taking shortcuts and borderline hacks
> > > > > > because of
> > > > > > this, while doing it right wouldn't be much harder. I'm not
> > > > > > looking to
> > > > > > blame or judge anyone, I don't know how this came into place.
> > > > > > But what
> > > > > > it is now is (IMO) a bad design and I feel the need to say it
> > > > > > after
> > > > > > working on it for quite some time ;)
> > > > >
> > > > > Doing it differently would lead to push the complexity higher
> > > > > up the
> > > > > stack, perhaps even to the user. We wanted to avoid that.
> > >
> > > I don't see how this could reach the user.
> > >
> > > >
> > > > Yeah, as I said, not sure what the reason was, but IMO you could
> > > > have
> > > > had that and still make it much more robust.
> > >
> > > I cannot say a car has a bad design because it does not have the
> > > load
> > > of a big truck, just a different use case. We probably started
> > > using
> > > the car (to continue the metaphor) to load some stuff and we are
> > > now
> > > exceeding the limit. At the beginning we though a car was enough :-
> > > )
> > >
> > > >
> > > > Oh and BTW, not sure how old this is, but I'm sure I'd have much
> > > > worse
> > > > things to say about the code _I_ wrote say like 8 years ago ;)
> > > >
> > > > > > > > Hope this explains it well enough. It's all very complex
> > > > > > > > and goes
> > > > > > > > over
> > > > > > > > multiple interfaces (the network protocols as well as the
> > > > > > > > spice-gtk
> > > > > > > > API), so the more brilliant ideas you'll have, the more
> > > > > > > > welcome they
> > > > > > > > will be :)
> > > > > > >
> > > > > > > If we can avoid modifying all the layers and exposing the
> > > > > > > inner
> > > > > > > details, I would encourage the exploration of other
> > > > > > > solution.
> > > > > >
> > > > > > I don't see how we can do that... And the inner details are
> > > > > > already
> > > > > > quite exposed, unfortunately :(
> > > > > >
> > > > > > As I said, ideas welcome.
> > > > > >
> > > > > > > > > > 1. The streaming-agent sends a new StreamInfo message
> > > > > > > > > > when it
> > > > > > > > > > starts
> > > > > > > > > > streaming. The message contains the output_id of the
> > > > > > > > > > streamed
> > > > > > > > > > monitor.
> > > > > > > > > > The actual value is the index in the list of xrandr
> > > > > > > > > > outputs.
> > > > > > > > > > Basically,
> > > > > > > > > > the number should uniquely identify a monitor in the
> > > > > > > > > > guest
> > > > > > > > > > context under
> > > > > > > > > > X.
> > > > > > > > > >
> > > > > > > > > > 2. The server copies the number into the
> > > > > > > > > > SpiceMsgDisplayMonitorsConfig
> > > > > > > > > > message and sends it to the client as part of the
> > > > > > > > > > monitors_config
> > > > > > > > > > exchange.
> > > > > > > > > >
> > > > > > > > > > 3. The client stores the output_id in it's list of
> > > > > > > > > > monitor_configs. Here
> > > > > > > > > > I had to make significant changes, because the
> > > > > > > > > > monitors_config
> > > > > > > > > > code in
> > > > > > > > > > spice-gtk is very loosely written and also exposes
> > > > > > > > > > quite a few
> > > > > > > > > > unnecessary details to the client app. The client
> > > > > > > > > > sends the
> > > > > > > > > > output_id
> > > > > > > > > > back to the server as part of the monitors_config
> > > > > > > > > > messages
> > > > > > > > > > (VDAgentMonitorsConfigV2) and also uses it for the
> > > > > > > > > > mouse motion
> > > > > > > > > > event,
> > > > > > > > > > which also contains a display ID interpreted by the
> > > > > > > > > > vd_agent. In
> > > > > > > > > > the
> > > > > > > > > > end, the API/ABI towards the client app should remain
> > > > > > > > > > unchanged.
> > > > > > > > > >
> > > > > > > > > > 4. The server passes the output_id in above-mentioned
> > > > > > > > > > messages to
> > > > > > > > > > the
> > > > > > > > > > vd_agent. The output_id is meaningless in the server
> > > > > > > > > > context.
> > > > > > > > > > (Currently, it doesn't pass the monitors_config
> > > > > > > > > > messages if there
> > > > > > > > > > is a
> > > > > > > > > > QXL device that supports it, though. Needs more
> > > > > > > > > > work.)
> > > > > > > > > >
> > > > > > > > > > 5. vd_agent:
> > > > > > > > > > a) For mouse input, the output_id was passed in the
> > > > > > > > > > original
> > > > > > > > > > message,
> > > > > > > > > > so no change needed here, it works.
> > > > > > > > > >
> > > > > > > > > > b) If the server sends monitors_config to the
> > > > > > > > > > guest, the
> > > > > > > > > > vdagent will
> > > > > > > > > > prefer to use monitors_configs with the output_ids
> > > > > > > > > > set, if such
> > > > > > > > > > are
> > > > > > > > > > present. In that case, it ignores monitors_configs
> > > > > > > > > > with the
> > > > > > > > > > output_id
> > > > > > > > > > unset. If no output_ids are present, it should
> > > > > > > > > > behave as it
> > > > > > > > > > used to.
> > > > > > > > > >
> > > > > > > > > > A couple of things to note:
> > > > > > > > > > - While I did copy the VDAgentMonitorsConfig to a
> > > > > > > > > > different
> > > > > > > > > > message for
> > > > > > > > > > backwards compatibility, I didn't do the same for
> > > > > > > > > > SpiceMsgDisplayMonitorsConfig, it remains to be done.
> > > > > > > > > >
> > > > > > > > > > - I didn't introduce any capabilities to handle the
> > > > > > > > > > compatibility, also
> > > > > > > > > > remains to be done. Hopefully it is also clear it
> > > > > > > > > > will be quite a
> > > > > > > > > > non-trivial job to do that :( Ain't gonna make the
> > > > > > > > > > code prettier
> > > > > > > > > > either.
> > > > > > > > > >
> > > > > > > > > > For your convenience, you can also pull the branches
> > > > > > > > > > below:
> > > > > > > > > > https://gitlab.freedesktop.org/lukash/spice-protocol/
> > > > > > > > > > tree/monitors-config-poc
> > > > > > > > > > https://gitlab.freedesktop.org/lukash/spice-common/tr
> > > > > > > > > > ee/monitors-config-poc
> > > > > > > > > > https://gitlab.com/lhrazky/spice-streaming-agent/tree
> > > > > > > > > > /monitors-config-poc
> > > > > > > > > > https://gitlab.freedesktop.org/lukash/spice/tree/moni
> > > > > > > > > > tors-config-poc
> > > > > > > > > > https://gitlab.freedesktop.org/lukash/spice-gtk/tree/
> > > > > > > > > > monitors-config-poc
> > > > > > > > > > https://gitlab.freedesktop.org/lukash/vd_agent/tree/m
> > > > > > > > > > onitors-config-poc
> > > > > > > > > >
> > > > > > > > > > All in all, it's big, complex and invasive. Note I
> > > > > > > > > > did review the
> > > > > > > > > > emergency instructional video [1] and am therefore
> > > > > > > > > > ready for any
> > > > > > > > > > bombardment you'll be sending my way :D (Don't
> > > > > > > > > > hesitate to
> > > > > > > > > > contact me
> > > > > > > > > > with questions either)
> > > > > > > > > >
> > > > > > > > > > Last minute note: I've noticed some of the patches
> > > > > > > > > > are missing
> > > > > > > > > > Signed-off-by line, since they are not for merging,
> > > > > > > > > > should not be
> > > > > > > > > > an
> > > > > > > > > > issue...
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Lukáš Hrázký (16):
> > > > > > > > > > spice-protocol
> > > > > > > > > > Add the StreamInfo message
> > > > > > > > > > Create a version 2 of the VDAgentMonitorsConfig
> > > > > > > > > > message
> > > > > > > > > > spice-common
> > > > > > > > > > add output_id to SpiceMsgDisplayMonitorsConfig
> > > > > > > > > > spice-streaming-agent
> > > > > > > > > > Send a StreamInfo message when starting to stream
> > > > > > > > > > spice-server
> > > > > > > > > > Handle the StreamInfo message from the streaming
> > > > > > > > > > agent
> > > > > > > > > > Use VDAgentMonitorsConfigV2 that contains the
> > > > > > > > > > output_id field
> > > > > > > > > > spice-gtk
> > > > > > > > > > Rework the handling of monitors_config
> > > > > > > > > > Remove the n_display_channels check when sending
> > > > > > > > > > monitors_config
> > > > > > > > > > Use an 'enabled' flag instead of status enum in
> > > > > > > > > > monitors_config
> > > > > > > > > > Use VDAgentMonitorsConfigV2 as the message for
> > > > > > > > > > monitors_config
> > > > > > > > > > Add output_id to the monitors_config
> > > > > > > > > > Use the new output_id as display ID for the mouse
> > > > > > > > > > motion event
> > > > > > > > > > vd_agent
> > > > > > > > > > vdagent: Log the diddly doo X11 error
> > > > > > > > > > Improve/add some logging messages
> > > > > > > > > > Use VDAgentMonitorsConfigV2 instead of
> > > > > > > > > > VDAgentMonitorsConfig
> > > > > > > > > > vdagent: Use output_id from VDAgentMonitorsConfigV2
> > > > > > > > > >
> > > > > > > > > > [1] https://www.youtube.com/watch?v=IKqXu-5jw60
> > > > > > > > > >
> > >
> > > Frediano
> >
> > _______________________________________________
> > Spice-devel mailing list
> > Spice-devel@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/spice-devel
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