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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/ANDROID-QEMUD.TXT | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/docs/ANDROID-QEMUD.TXT b/docs/ANDROID-QEMUD.TXT index 1364553..7841399 100644 --- a/docs/ANDROID-QEMUD.TXT +++ b/docs/ANDROID-QEMUD.TXT @@ -249,3 +249,27 @@ but lacked a lot of flexibility: The current implementation moves any service-specific code to the emulator, only uses a single socket and allows concurrent clients for a all services. + + +IV. State snapshots: +-------------------- + +Support for snapshots relies on the symmetric qemud_*_save and qemud_*_load +functions which save the state of the various Qemud* structs defined in +android/hw-qemud.c. The high-level process is as follows. + +When a snapshot is made, the names and configurations of all services are +saved. Services can register a custom callback, which is invoked at this point +to allow saving of service-specific state. Next, clients are saved following +the same pattern. We save the channel id and the name of service they are +registered to, then invoke a client-specific callback. + +When a snapshot is restored, the first step is to check whether all services +that were present when the snapshot was made are available. There is currently +no functionality to start start missing services, so loading fails if a service +is not present. If all services are present, callbacks are used to restore +service-specific state. + +Next, all active clients are shut down. Information from the snapshot is used +to start new clients for the services and channels as they were when the +snapshot was made. This completes the restore process. |