Weston Plugin Based IVI Layer Management. Ossama Othman 20 September 2012

Transcription

1 Weston Plugin Based IVI Layer Management Ossama Othman 20 September 2012

2 Context GNU/Linux based IVI platform Multiple screens Multiple ECUs Applications may be distributed across multiple screens and ECUs IVI-specific UI paradigms 2

3 Problems Minimal resources for in-house development of suitable IVI compositor, etc. Costs Lack of expertise in interface between user space, kernel and graphics hardware Existing desktop solutions may not satisfy IVI UI requirements Compositor User Space Input Framework Kernel KMS evdev DRM Graphics Driver Hardware Graphics Input 3

4 Solution Wayland and Weston Core compositing functionality Handle kernel-space interaction Wayland Client Wayland Client Efficient IPC Open-source FTW! Weston Weston IVI plugin Addresses IVI related UI feature gaps in Weston Simple and focused Backend Shell IVI Shell Plugin 4

5 5 Weston IVI Plugin Interface for GENIVI -style Layer Management

6 Identifying Feature Gaps GENIVI Layer Management Client Interface Feature Surface Lifecycle Management Surface Positioning Surface Visibility Surface Opacity Layer Lifecycle Management Layer Positioning Layer Visibility Render order of surfaces in layer Wayland Protocol Yes Yes, but through input device, not client supplied coordinate No No No No No No 6

7 Writing the Weston IVI Plugin Interface Group operations according to layer management object type Surface Layer Display Weston plugin interface format matches Wayland protocol format Map Wayland protocol interface to each object type One Wayland request per feature (operation) Set position, opacity, visibility, etc 7

8 Wayland Protocol Interface XML Format <protocol name="ivi_shell"> <interface name="lm_surface" version="1"> <description summary=application graphical content"> Applications render content into a surface. </description> <request name="set_visibility"> <arg name="visibility" type="uint" summary="visibility /> </request> <event name="visibility"> <arg name="visibility" type="uint" summary="visibility /> </event> </interface> </protocol> 8

9 Subset of Wayland Protocol Elements Protocol XML Element protocol interface request event Description Top-level element that affects how files and #include guards generated by wayland-scanner are named Element that encapsulates a set of operations that may be performed on a corresponding instance Server side operation called on object by client that is completed asynchronously Client side operation asynchronously called by server side (e.g. Weston) when a change occurs 9

10 Wayland Protocol Argument Types Wayland Argument Type Native Type Description int int32_t 32 bit signed integer uint uint32_t 32 bit unsigned integer fixed wl_fixed_t double-precision floating point type, convert to native double using wl_fixed_{to,from}_double() string char const * nil-terminated C string array struct wl_array * Structure containing pointer to array and its length fd int open file descriptor new_id object struct wl_object * or struct wl_resource * struct wl_object * or struct wl_resource * Object reference passed to factory-like requests Object reference (e.g. instance of wl_surface) 10

11 Caveats No concept of synchronous return values e.g. get operations - in Wayland protocol Clients should cache old value until event arrives asynchronously with new value 11

12 12 Weston IVI Plugin Implementation

13 Weston Plugin Requirements Plugin entry point Initialization function called by Weston compositor upon successful load of plugin int module_init(struct weston_compositor *); Previously shell_init() Plugin must currently be built inside Weston source tree Weston does not yet export plugin interface or library 13

14 Weston Plugin Components ivi-shell.xml Wayland protocol based plugin interface wayland-scanner ivi-shell.xml ivi-shell.c Plugin implementation ivi-shell-server-protocol.h ivi-shell-protocol.c Generated files ivi-shell-server-protocol.h ivi-shell-protocol.c ivi-shell.c 14

15 Weston Plugin Implementation Request implementation prototypes found in generated ivi-shell-serverprotocol.h header static void lm_surface_set_opacity(struct wl_client * client, struct wl_resource * resource, struct wl_resource * opacity_resource); static const struct lm_surface_interface lm_surface_implementation = { lm_surface_set_opacity }; Register implementation struct wl_resource * resource = wl_client_add_object(client, &lm_surface_interface, &lm_surface_implementation, id, surface); 15

16 16 Using the Weston IVI Plugin

17 Configure Weston to Use IVI Plugin weston.ini search path $XDG_CONFIG_HOME/.config/ $HOME/.config/ Automake-style plugin install directory $(libdir)/weston/ Set name of plugin in weston.ini [shell] type=ivi-shell.so 17

18 Invocation of IVI Plugin Operations Client side build Add ivi-shell-protocol.c to client source build Client side code #include ivi-shell-client-protocol.h void foo() { lm_surface_set_visibility( ); } 18

19 19 Weston IVI Plugin vs. GENIVI Layer Manager

20 Architectures Client GENIVI LM Client Library Weston IVI Plugin Client GENIVI LM Client Library Communicator Plugin GENIVI Layer Manager Communicator Plugin Rendering Plugin libwayland IVI Plugin Client Stub Wayland IPC LM Communicator IPC (e.g. D-Bus, TCP/IP, etc) 20

21 Architectural Comparison Weston IVI Plugin Weston-specific Small codebase Efficient IPC Simple architecture Network transparency support in Wayland/Weston is still pending GENIVI Layer Manager Highly extensible Rendering plugins Wayland X Direct FB Communicator plugins D-Bus TCP/IP 21

22 Summary Existing desktop style window management is insufficient for IVI in some cases Applications are not necessarily run in windows Weston s extensibility is key to creating IVI UI with minimal effort No need for IVI UI developers to create compositor from scratch Allows IVI UI developers to focus on their own IVI-specific needs 22

23 References Wayland GENIVI Media & Graphics Expert Group 23

24 Legal INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH INTEL PRODUCTS. EXCEPT AS PROVIDED IN INTEL'S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, INTEL ASSUMES NO LIABILITY WHATSOEVER, AND INTEL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO SALE AND/OR USE OF INTEL PRODUCTS, INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT, OR OTHER INTELLECTUAL PROPERTY RIGHT. Intel may make changes to specifications, product descriptions, and plans at any time, without notice. All dates provided are subject to change without notice. Intel is a trademark of Intel Corporation in the U.S. and other countries. *Other names and brands may be claimed as the property of others. Copyright 2012, Intel Corporation. All rights are protected. 24

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