Core wayland protocol - generate pointer_focus (and drag focus) on raise/lower, move windows, all kinds of changes in surface stacking. - make a client side circular buffer of pending ping requests with callbacks and data. if buffer fills up, just iterate until an entry becomes available. wl_display_ping(dpy, func, data), basically. func is called when the reply comes in for the ping request. - glyph cache - dnd, figure out large object transfer: through wayland protocol or pass an fd through the compositor to the other client and let them sort it out? - DnD issues: How to roboustly handle failing drag, ie the case where an application gets a button event, tries to activate a drag, but when the server gets the drag request, the button has already been released and the grab is no longer active. What's the concern: - Application may set a drag cursor that doesn't revert back, since a failed drag doesn't result in a pointer_focus event to give focus back to the surface. We could just do that: if the pointer_focus is the same surface as we tried to start a grab for, just remove and give back pointer_focus. Alternatively, set drag cursors only in response to drag events, like drag focus. But drag_focus and drag_motion are sent to the drag target, so the source surface won't always get those. We may also end up setting the cursor after the drag ends, but in this case the drag started and ended and we'll get a pointer_focus event, which will make the application reset the pointer image. Could introduce a drag start event that indicates that the drag active. How to handle drop decline (accept with type=NULL) - Targets must send a NULL type in accept if they don't accept a drop at the drag_focus/drag_motion position. Root window will send a NULL type or x-wayland/root-something type if the source offers that. Races between pointer motion, ending the drag, the target sending accept request and the source receiving the target event. - We've sent a drag focus or motion event to the source, but haven't received an accept request corresponding to that event and now the button is release. The compositor could wait for the source to reply to outstanding focus/motion events before sending the finish event to the source. Or we could send the finish event through the source so that it needs to reply to the finish event too. Either way, the state of the drag blocks on the client. What if we drag to a client that doesn't doo dnd? How do we animate the drag icon back to the drag origin in case of a failed drag? How to handle surfaces from clients that don't know about dnd or don't care? Maybe the dnd object should have a dnd.register_surface() method so clients can opt-in the surfaces that will participate in dnd. Or just assume client is not participating until we receive an accept request. May need to look at all offer events before we can decide which one to go with. Problem is, we don't know when we've seen that last offer event. Create transient dnd object when a client starts a drag. Announce the dnd object to clients first time the drag enters one of its surfaces. Track if we've already announced the object by comparing the drag start timestamp/serial with the clients last-event timestamp/serial? Wont work if we send other events to a client after creating the drag object. Maybe just keep the transient object on the initiator side? - Pointer image issue: - A touch input device doesn't have a pointer; indicate that somehow. - Cursor themes - copy-n-paste, store data in server (only one mime-type available) or do X style (content mime-type negotiation, but data goes away when client quits). - Discard buffer, as in "wayland discarded your buffer, it's no longer visible, you can stop updating it now.", reattach, as in "oh hey, I'm about to show your buffer that I threw away, what was it again?". for wayland system compositor vt switcing, for example, to be able to throw away the surfaces in the session we're switching away from. for minimized windows that we don't want live thumb nails for. etc. - Initial placement of surfaces. Guess we can do, 1) surface-relative (menus), 2) pointer-relative (tooltips and right-click menus) or 3) server-decides (all other top-levels). - When a surface is the size of the screen and on top, we can set the scanout buffer to that surface directly. Like compiz unredirect top-level window feature. Except it won't have any protocol state side-effects and the client that owns the surface won't know. We lose control of updates. Should work well for X server root window under wayland. Should be possible for yuv overlays as well. - what about cursors then? maybe use hw cursors if the cursor satisfies hw limitations (64x64, only one cursor), switch to composited cursors if not. - clients needs to allocate the surface to be suitable for scanout, which they can do whenever they go fullscreen. - multihead, screen geometry and crtc layout protocol, hotplug - input device discovery, hotplug - Advertise axes as part of the discovery, use something like "org.wayland.input.x" to identify the axes. - keyboard state, layout events at connect time and when it changes, keyboard leds - relative events - multi touch? - synaptics, 3-button emulation, scim - Figure out if we need the batch/commit scheme and what to do instead. Since dropping the "copy" request, we have a race between copy from back to front and reporting damage. "copy" did this atomically, but copy is a rendering operation (wayland doesn't do rendering) and requires synchronization between server and client before client can reuse backbuffer. The race condition happens when a client copies new content into its window and then, before the client reports the damage, the compositor then does a partial repaint (triggered by another client) that only pulls in part of the repainted area. It's only a one-frame glitch, as the client will submit the damage and the compositor will repaint the damaged area next frame. And ideally clients should do all rendering as early in the frame as possible to avoid this race. - auth; We need to generate a random socket name and advertise that on dbus along with a connection cookie. Something like a method that returns the socket name and a connection cookie. The connection cookie is just another random string that the client must pass to the wayland server to become authenticated. The Wayland server generates the cookie on demand when the dbus method is called and expires it after 5s or so. - or just pass the fd over dbus - drm bo access control, authentication, flink_to - Range protocol may not be sufficient... if a server cycles through 2^32 object IDs we don't have a way to handle wrapping. And since we hand out a range of 256 IDs to each new clients, we're just talking about 2^24 clients. That's 31 years with a new client every minute... Maybe just use bigger ranges, then it's feasible to track and garbage collect them when a client dies. - Add protocol to let applications specify the effective/logical surface rectangle, that is, the edge of the window, ignoring drop shadows and other padding. The compositor needs this for snapping and constraining window motion. Also, maybe communicate the opaque region of the window (or just a conservative, simple estimate), to let the compositor reduce overdraw. - multi gpu, needs queue and seqno to wait on in requests Clients and ports - port gtk+ - eek, so much X legacy stuff there... - draw window decorations in gtkwindow.c - start from alexl's client-side-windows branch - Details about pointer grabs. wayland doesn't have active grabs, menus will behave subtly different. Under X, clicking a menu open grabs the pointer and clicking outside the window pops down the menu and swallows the click. without active grabs we can't swallow the click. I'm sure there much more... - Port Qt? There's already talk about this on the list. - X on Wayland - move most of the code from xf86-video-intel into a Xorg wayland module. - don't ask KMS for available output and modes, use the info from the wayland server. then stop mooching off of drmmode.c. - map multiple wayland input devices to MPX in Xorg. - rootless; avoid allocating and setting the front buffer, draw window decorations in the X server (!), how to map input? - gnome-shell as a wayland session compositor - runs as a client of the wayland session compositor, uses clutter+egl on wayland - talks to an Xorg server as the compositing and window manager for that server and renders the output to a wayland surface. the Xorg server should be modified to take input from the system compositor through gnome-shell, but not allocate a front buffer. - make gnome-shell itself a nested wayland server and allow native wayland clients to connect and can native wayland windows with the windows from the X server. - qemu as a wayland client; session surface as X case - qemu has too simple acceleration, so a Wayland backend like the SDL/VNC ones it has now is trivial. - paravirt: forward wayland screen info as mmio, expose gem ioctls as mmio - mapping vmem is tricky, should try to only use ioctl (pwrite+pread) - not useful for Windows without a windows paravirt driver. - two approaches: 1) do a toplevel qemu window, or 2) expose a wayland server in the guest that forwards to the host wayland server, ie a "remote" compositor, but with the gem buffers shared. could do a wl_connection directly on mmio memory, with head and tail pointers. use an alloc_head register to indicate desired data to write, if it overwrites tail, block guest. just a socket would be easier. - moblin as a wayland compositor - clutter as a wayland compositors - argh, mutter