text: /*
   * Copyright (C) 2010 The Android Open Source Project
   * Copyright (C) 2012, Code Aurora Forum. All rights reserved.
   *
   * Not a Contribution, Apache license notifications and license are
   * retained for attribution purposes only.
  
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  // WARNING : Excessive logging, if VSYNC_DEBUG enabled
  #define VSYNC_DEBUG 0
  
  #include <utils/Log.h>
  #include <fcntl.h>
  #include <sys/ioctl.h>
  #include <linux/msm_mdp.h>
  #include <sys/resource.h>
  #include <sys/prctl.h>
  #include "hwc_utils.h"
  #include "string.h"
  #include "external.h"
  
  
  namespace qhwc {
  
  #define HWC_VSYNC_THREAD_NAME "hwcVsyncThread"
  
  static void *vsync_loop(void *param)
  {
      const char* vsync_timestamp_fb0 = "/sys/class/graphics/fb0/vsync_event";
      const char* vsync_timestamp_fb1 = "/sys/class/graphics/fb1/vsync_event";
      int dpy = HWC_DISPLAY_PRIMARY;
  
      hwc_context_t * ctx = reinterpret_cast<hwc_context_t *>(param);
  
      char thread_name[64] = HWC_VSYNC_THREAD_NAME;
      prctl(PR_SET_NAME, (unsigned long) &thread_name, 0, 0, 0);
      setpriority(PRIO_PROCESS, 0, HAL_PRIORITY_URGENT_DISPLAY +
                  android::PRIORITY_MORE_FAVORABLE);
  
      const int MAX_DATA = 64;
      const int MAX_RETRY_COUNT = 100;
      static char vdata[MAX_DATA];
  
      uint64_t cur_timestamp=0;
      ssize_t len = -1;
      int fd_timestamp = -1;
      int ret = 0;
      bool fb1_vsync = false;
      bool enabled = false;
  
      /* Currently read vsync timestamp from drivers
         e.g. VSYNC=41800875994
      */
      fd_timestamp = open(vsync_timestamp_fb0, O_RDONLY);
      if (fd_timestamp < 0) {
          ALOGE ("FATAL:%s:not able to open file:%s, %s",  __FUNCTION__,
                 (fb1_vsync) ? vsync_timestamp_fb1 : vsync_timestamp_fb0,
                 strerror(errno));
          return NULL;
      }
  
      do {
          pthread_mutex_lock(&ctx->vstate.lock);
          while (ctx->vstate.enable == false) {
              if(enabled) {
                  int e = 0;
                  if(ioctl(ctx->dpyAttr[dpy].fd, MSMFB_OVERLAY_VSYNC_CTRL,
                           &e) < 0) {
                      ALOGE("%s: vsync control failed. Dpy=%d, enabled=%d : %s",
                            __FUNCTION__, dpy, enabled, strerror(errno));
                      ret = -errno;
                  }
                  enabled = false;
              }
              pthread_cond_wait(&ctx->vstate.cond, &ctx->vstate.lock);
          }
          pthread_mutex_unlock(&ctx->vstate.lock);
  
          if (!enabled) {
              int e = 1;
              if(ioctl(ctx->dpyAttr[dpy].fd, MSMFB_OVERLAY_VSYNC_CTRL,
                                            &e) < 0) {
                  ALOGE("%s: vsync control failed. Dpy=%d, enabled=%d : %s",
                        __FUNCTION__, dpy, enabled, strerror(errno));
                  ret = -errno;
              }
              enabled = true;
          }
  
         for(int i = 0; i < MAX_RETRY_COUNT; i++) {
             len = pread(fd_timestamp, vdata, MAX_DATA, 0);
             if(len < 0 && (errno == EAGAIN || errno == EINTR)) {
                 ALOGW("%s: vsync read: EAGAIN, retry (%d/%d).",
                       __FUNCTION__, i, MAX_RETRY_COUNT);
                 continue;
             } else {
                 break;
             }
         }
  
         if (len < 0) {
             ALOGE ("FATAL:%s:not able to read file:%s, %s", __FUNCTION__,
                    vsync_timestamp_fb0, strerror(errno));
             close (fd_timestamp);
             return NULL;
         }
  
         // extract timestamp
         const char *str = vdata;
         if (!strncmp(str, "VSYNC=", strlen("VSYNC="))) {
            cur_timestamp = strtoull(str + strlen("VSYNC="), NULL, 0);
         } else {
            ALOGE ("FATAL: %s: vsync timestamp not in correct format: [%s]",
                    __FUNCTION__,
                    str);
         }
         // send timestamp to HAL
         ALOGD_IF (VSYNC_DEBUG, "%s: timestamp %llu sent to HWC for %s",
              __FUNCTION__, cur_timestamp, "fb0");
         ctx->proc->vsync(ctx->proc, dpy, cur_timestamp);
  
      } while (true);
      if(fd_timestamp >= 0)
          close (fd_timestamp);
  
      return NULL;
  }
  
  void init_vsync_thread(hwc_context_t* ctx)
  {
      int ret;
      pthread_t vsync_thread;
      ALOGI("Initializing VSYNC Thread");
      ret = pthread_create(&vsync_thread, NULL, vsync_loop, (void*) ctx);
      if (ret) {
          ALOGE("%s: failed to create %s: %s", __FUNCTION__,
              HWC_VSYNC_THREAD_NAME, strerror(ret));
      }
  }
  
  }; //namespace
  