Merge "Revert "libsuspend: move to exponential backoff"" into nyc-mr1-dev

#include <stddef.h>

#include <stdbool.h>

#include <string.h>

#include <sys/param.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <unistd.h>

#define SYS_POWER_STATE "/sys/power/state"

#define SYS_POWER_WAKEUP_COUNT "/sys/power/wakeup_count"

#define BASE_SLEEP_TIME 100000

static int state_fd;

static int wakeup_count_fd;

static pthread_t suspend_thread;

static sem_t suspend_lockout;

static const char *sleep_state = "mem";

static void (*wakeup_func)(bool success) = NULL;

static int sleep_time = BASE_SLEEP_TIME;

static void update_sleep_time(bool success) {

    if (success) {

        sleep_time = BASE_SLEEP_TIME;

        return;

    }

    // double sleep time after each failure up to one minute

    sleep_time = MIN(sleep_time * 2, 60000000);

}

static void *suspend_thread_func(void *arg __attribute__((unused)))

{

    char wakeup_count[20];

    int wakeup_count_len;

    int ret;

    bool success = true;

    bool success;

    while (1) {

        update_sleep_time(success);

        usleep(sleep_time);

        success = false;

        usleep(100000);

        ALOGV("%s: read wakeup_count\n", __func__);

        lseek(wakeup_count_fd, 0, SEEK_SET);

        wakeup_count_len = TEMP_FAILURE_RETRY(read(wakeup_count_fd, wakeup_count,

            continue;

        }

        success = true;

        ALOGV("%s: write %*s to wakeup_count\n", __func__, wakeup_count_len, wakeup_count);

        ret = TEMP_FAILURE_RETRY(write(wakeup_count_fd, wakeup_count, wakeup_count_len));

        if (ret < 0) {

        } else {

            ALOGV("%s: write %s to %s\n", __func__, sleep_state, SYS_POWER_STATE);

            ret = TEMP_FAILURE_RETRY(write(state_fd, sleep_state, strlen(sleep_state)));

            if (ret >= 0) {

                success = true;

            if (ret < 0) {

                success = false;

            }

            void (*func)(bool success) = wakeup_func;

            if (func != NULL) {