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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "Fence"
     18 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
     19 //#define LOG_NDEBUG 0
     20 
     21 // We would eliminate the non-conforming zero-length array, but we can't since
     22 // this is effectively included from the Linux kernel
     23 #pragma clang diagnostic push
     24 #pragma clang diagnostic ignored "-Wzero-length-array"
     25 #include <sync/sync.h>
     26 #pragma clang diagnostic pop
     27 
     28 #include <ui/Fence.h>
     29 #include <unistd.h>
     30 #include <utils/Log.h>
     31 #include <utils/Trace.h>
     32 
     33 namespace android {
     34 
     35 const sp<Fence> Fence::NO_FENCE = sp<Fence>(new Fence);
     36 
     37 Fence::Fence() :
     38     mFenceFd(-1) {
     39 }
     40 
     41 Fence::Fence(int fenceFd) :
     42     mFenceFd(fenceFd) {
     43 }
     44 
     45 Fence::~Fence() {
     46     if (mFenceFd != -1) {
     47         close(mFenceFd);
     48     }
     49 }
     50 
     51 status_t Fence::wait(int timeout) {
     52     ATRACE_CALL();
     53     if (mFenceFd == -1) {
     54         return NO_ERROR;
     55     }
     56     int err = sync_wait(mFenceFd, timeout);
     57     return err < 0 ? -errno : status_t(NO_ERROR);
     58 }
     59 
     60 status_t Fence::waitForever(const char* logname) {
     61     ATRACE_CALL();
     62     if (mFenceFd == -1) {
     63         return NO_ERROR;
     64     }
     65     int warningTimeout = 3000;
     66     int err = sync_wait(mFenceFd, warningTimeout);
     67     if (err < 0 && errno == ETIME) {
     68         ALOGE("%s: fence %d didn't signal in %u ms", logname, mFenceFd,
     69                 warningTimeout);
     70         err = sync_wait(mFenceFd, TIMEOUT_NEVER);
     71     }
     72     return err < 0 ? -errno : status_t(NO_ERROR);
     73 }
     74 
     75 sp<Fence> Fence::merge(const String8& name, const sp<Fence>& f1,
     76         const sp<Fence>& f2) {
     77     ATRACE_CALL();
     78     int result;
     79     // Merge the two fences.  In the case where one of the fences is not a
     80     // valid fence (e.g. NO_FENCE) we merge the one valid fence with itself so
     81     // that a new fence with the given name is created.
     82     if (f1->isValid() && f2->isValid()) {
     83         result = sync_merge(name.string(), f1->mFenceFd, f2->mFenceFd);
     84     } else if (f1->isValid()) {
     85         result = sync_merge(name.string(), f1->mFenceFd, f1->mFenceFd);
     86     } else if (f2->isValid()) {
     87         result = sync_merge(name.string(), f2->mFenceFd, f2->mFenceFd);
     88     } else {
     89         return NO_FENCE;
     90     }
     91     if (result == -1) {
     92         status_t err = -errno;
     93         ALOGE("merge: sync_merge(\"%s\", %d, %d) returned an error: %s (%d)",
     94                 name.string(), f1->mFenceFd, f2->mFenceFd,
     95                 strerror(-err), err);
     96         return NO_FENCE;
     97     }
     98     return sp<Fence>(new Fence(result));
     99 }
    100 
    101 int Fence::dup() const {
    102     return ::dup(mFenceFd);
    103 }
    104 
    105 nsecs_t Fence::getSignalTime() const {
    106     if (mFenceFd == -1) {
    107         return -1;
    108     }
    109 
    110     struct sync_fence_info_data* finfo = sync_fence_info(mFenceFd);
    111     if (finfo == NULL) {
    112         ALOGE("sync_fence_info returned NULL for fd %d", mFenceFd);
    113         return -1;
    114     }
    115     if (finfo->status != 1) {
    116         sync_fence_info_free(finfo);
    117         return INT64_MAX;
    118     }
    119 
    120     struct sync_pt_info* pinfo = NULL;
    121     uint64_t timestamp = 0;
    122     while ((pinfo = sync_pt_info(finfo, pinfo)) != NULL) {
    123         if (pinfo->timestamp_ns > timestamp) {
    124             timestamp = pinfo->timestamp_ns;
    125         }
    126     }
    127     sync_fence_info_free(finfo);
    128 
    129     return nsecs_t(timestamp);
    130 }
    131 
    132 size_t Fence::getFlattenedSize() const {
    133     return 4;
    134 }
    135 
    136 size_t Fence::getFdCount() const {
    137     return isValid() ? 1 : 0;
    138 }
    139 
    140 status_t Fence::flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const {
    141     if (size < getFlattenedSize() || count < getFdCount()) {
    142         return NO_MEMORY;
    143     }
    144     // Cast to uint32_t since the size of a size_t can vary between 32- and
    145     // 64-bit processes
    146     FlattenableUtils::write(buffer, size, static_cast<uint32_t>(getFdCount()));
    147     if (isValid()) {
    148         *fds++ = mFenceFd;
    149         count--;
    150     }
    151     return NO_ERROR;
    152 }
    153 
    154 status_t Fence::unflatten(void const*& buffer, size_t& size, int const*& fds, size_t& count) {
    155     if (mFenceFd != -1) {
    156         // Don't unflatten if we already have a valid fd.
    157         return INVALID_OPERATION;
    158     }
    159 
    160     if (size < 1) {
    161         return NO_MEMORY;
    162     }
    163 
    164     uint32_t numFds;
    165     FlattenableUtils::read(buffer, size, numFds);
    166 
    167     if (numFds > 1) {
    168         return BAD_VALUE;
    169     }
    170 
    171     if (count < numFds) {
    172         return NO_MEMORY;
    173     }
    174 
    175     if (numFds) {
    176         mFenceFd = *fds++;
    177         count--;
    178     }
    179 
    180     return NO_ERROR;
    181 }
    182 
    183 } // namespace android
    184