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Commit f33b2b2b authored by Jeff Brown's avatar Jeff Brown
Browse files

Recover from bad input event timestamps from the kernel. 

This can happen due to a race when the input device is
opened or if the kernel happens to be missing the required
Android patches to set the timestamp correctly.

Bug: 7291243
Change-Id: If4319440eaff2889147c86296abd39efc5664346
parent f9485002

services/input/EventHub.cpp

+34 −0
Original line number Diff line number Diff line
@@ -787,6 +787,40 @@ size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSiz 
                        event->when = nsecs_t(iev.time.tv_sec) * 1000000000LL

                                + nsecs_t(iev.time.tv_usec) * 1000LL;

                        ALOGV("event time %lld, now %lld", event->when, now);



                        // Bug 7291243: Add a guard in case the kernel generates timestamps

                        // that appear to be far into the future because they were generated

                        // using the wrong clock source.

                        //

                        // This can happen because when the input device is initially opened

                        // it has a default clock source of CLOCK_REALTIME.  Any input events

                        // enqueued right after the device is opened will have timestamps

                        // generated using CLOCK_REALTIME.  We later set the clock source

                        // to CLOCK_MONOTONIC but it is already too late.

                        //

                        // Invalid input event timestamps can result in ANRs, crashes and

                        // and other issues that are hard to track down.  We must not let them

                        // propagate through the system.

                        //

                        // Log a warning so that we notice the problem and recover gracefully.

                        if (event->when >= now + 10 * 1000000000LL) {

                            // Double-check.  Time may have moved on.

                            nsecs_t time = systemTime(SYSTEM_TIME_MONOTONIC);

                            if (event->when > time) {

                                ALOGW("An input event from %s has a timestamp that appears to "

                                        "have been generated using the wrong clock source "

                                        "(expected CLOCK_MONOTONIC): "

                                        "event time %lld, current time %lld, call time %lld.  "

                                        "Using current time instead.",

                                        device->path.string(), event->when, time, now);

                                event->when = time;

                            } else {

                                ALOGV("Event time is ok but failed the fast path and required "

                                        "an extra call to systemTime: "

                                        "event time %lld, current time %lld, call time %lld.",

                                        event->when, time, now);

                            }

                        }

#else

                        event->when = now;

#endif

services/input/InputReader.cpp

+3 −2
Original line number Diff line number Diff line
@@ -956,8 +956,9 @@ void InputDevice::process(const RawEvent* rawEvents, size_t count) { 
    size_t numMappers = mMappers.size();

    for (const RawEvent* rawEvent = rawEvents; count--; rawEvent++) {

#if DEBUG_RAW_EVENTS

        ALOGD("Input event: device=%d type=0x%04x code=0x%04x value=0x%08x",

                rawEvent->deviceId, rawEvent->type, rawEvent->code, rawEvent->value);

        ALOGD("Input event: device=%d type=0x%04x code=0x%04x value=0x%08x when=%lld",

                rawEvent->deviceId, rawEvent->type, rawEvent->code, rawEvent->value,

                rawEvent->when);

#endif



        if (mDropUntilNextSync) {