Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 64289760 authored by Greg Hackmann's avatar Greg Hackmann
Browse files

SystemClock: use clock_gettime() on devices without /dev/alarm 



On devices with an up-to-date kernel, the back-in-time bug affecting
clock_gettime() has been fixed and it can safely be used as an
alternative to the ANDROID_ALARM_GET_TIME ioctl.  To ensure consistent
behavior on existing devices, make clock_gettime() a fallback for when
the alarm driver isn't available.

Change-Id: I384af5e7ec9e73e0bad4b6b0f987a8ea4583cba6
Signed-off-by: default avatarGreg Hackmann <ghackmann@google.com>
parent a585e662

libutils/SystemClock.cpp

+9 −16
Original line number Diff line number Diff line
@@ -119,22 +119,6 @@ int64_t elapsedRealtimeNano() 
    static volatile int prevMethod;

#endif



#if 0

    /*

     * b/7100774

     * clock_gettime appears to have clock skews and can sometimes return

     * backwards values. Disable its use until we find out what's wrong.

     */

    result = clock_gettime(CLOCK_BOOTTIME, &ts);

    if (result == 0) {

        timestamp = seconds_to_nanoseconds(ts.tv_sec) + ts.tv_nsec;

        checkTimeStamps(timestamp, &prevTimestamp, &prevMethod,

                        METHOD_CLOCK_GETTIME);

        return timestamp;

    }

#endif



    // CLOCK_BOOTTIME doesn't exist, fallback to /dev/alarm

    static int s_fd = -1;



    if (s_fd == -1) {
@@ -153,6 +137,15 @@ int64_t elapsedRealtimeNano() 
        return timestamp;

    }



    // /dev/alarm doesn't exist, fallback to CLOCK_BOOTTIME

    result = clock_gettime(CLOCK_BOOTTIME, &ts);

    if (result == 0) {

        timestamp = seconds_to_nanoseconds(ts.tv_sec) + ts.tv_nsec;

        checkTimeStamps(timestamp, &prevTimestamp, &prevMethod,

                        METHOD_CLOCK_GETTIME);

        return timestamp;

    }



    // XXX: there was an error, probably because the driver didn't

    // exist ... this should return

    // a real error, like an exception!