Return-Path: From: Andrzej Kaczmarek To: linux-bluetooth@vger.kernel.org Cc: Andrzej Kaczmarek Subject: [PATCH v2 3/6] android/hal-audio: Make audio socket non-blocking Date: Thu, 17 Apr 2014 01:50:35 +0200 Message-Id: <1397692238-18642-3-git-send-email-andrzej.kaczmarek@tieto.com> In-Reply-To: <1397692238-18642-1-git-send-email-andrzej.kaczmarek@tieto.com> References: <1397692238-18642-1-git-send-email-andrzej.kaczmarek@tieto.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: This patch makes writing to audio socket non-blocking since there's no point in waiting indefinitely to write some data. Instead, we wait no more than 500ms for socket to be ready and just skip packet otherwise. --- android/hal-audio.c | 191 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 130 insertions(+), 61 deletions(-) diff --git a/android/hal-audio.c b/android/hal-audio.c index 992fdf7..a261871 100644 --- a/android/hal-audio.c +++ b/android/hal-audio.c @@ -147,6 +147,27 @@ static void timespec_add(struct timespec *base, uint64_t time_us, } } +static void timespec_diff(struct timespec *a, struct timespec *b, + struct timespec *res) +{ + res->tv_sec = a->tv_sec - b->tv_sec; + res->tv_nsec = a->tv_nsec - b->tv_nsec; + + if (res->tv_nsec < 0) { + res->tv_sec--; + res->tv_nsec += 1000000000; /* 1sec */ + } +} + +static uint64_t timespec_diff_us(struct timespec *a, struct timespec *b) +{ + struct timespec res; + + timespec_diff(a, b, &res); + + return res.tv_sec * 1000000ll + res.tv_nsec / 1000ll; +} + #if defined(ANDROID) /* Bionic does not have clock_nanosleep() prototype in time.h even though * it provides its implementation. @@ -830,26 +851,6 @@ static void unregister_endpoints(void) } } -static int set_blocking(int fd) -{ - int flags; - - flags = fcntl(fd, F_GETFL, 0); - if (flags < 0) { - int err = -errno; - error("fcntl(F_GETFL): %s (%d)", strerror(-err), -err); - return err; - } - - if (fcntl(fd, F_SETFL, flags & ~O_NONBLOCK) < 0) { - int err = -errno; - error("fcntl(F_SETFL): %s (%d)", strerror(-err), -err); - return err; - } - - return 0; -} - static bool open_endpoint(struct audio_endpoint *ep, struct audio_input_config *cfg) { @@ -863,9 +864,6 @@ static bool open_endpoint(struct audio_endpoint *ep, AUDIO_STATUS_SUCCESS) return false; - if (set_blocking(fd) < 0) - goto failed; - DBG("mtu=%u", mtu); payload_len = mtu - sizeof(*ep->mp); @@ -915,7 +913,6 @@ static bool resume_endpoint(struct audio_endpoint *ep) if (ipc_resume_stream_cmd(ep->id) != AUDIO_STATUS_SUCCESS) return false; - clock_gettime(CLOCK_MONOTONIC, &ep->start); ep->samples = 0; return true; @@ -936,6 +933,64 @@ static void downmix_to_mono(struct a2dp_stream_out *out, const uint8_t *buffer, } } +static bool wait_for_endpoint(struct audio_endpoint *ep, bool *writable) +{ + int ret; + + while (true) { + struct pollfd pollfd; + + pollfd.fd = ep->fd; + pollfd.events = POLLOUT; + pollfd.revents = 0; + + ret = poll(&pollfd, 1, 500); + + if (ret >= 0) { + *writable = !!(pollfd.revents & POLLOUT); + break; + } + + if (errno != EINTR) { + ret = errno; + error("poll failed (%d)", ret); + return false; + } + } + + return true; +} + +static bool write_to_endpoint(struct audio_endpoint *ep, size_t bytes) +{ + struct media_packet *mp = (struct media_packet *) ep->mp; + int ret; + + while (true) { + ret = write(ep->fd, mp, sizeof(*mp) + bytes); + + if (ret >= 0) + break; + + /* this should not happen so let's issue warning, but do not + * fail, we can try to write next packet + */ + if (errno == EAGAIN) { + ret = errno; + warn("write failed (%d)", ret); + break; + } + + if (errno != EINTR) { + ret = errno; + error("write failed (%d)", ret); + return false; + } + } + + return true; +} + static bool write_data(struct a2dp_stream_out *out, const void *buffer, size_t bytes) { @@ -949,58 +1004,72 @@ static bool write_data(struct a2dp_stream_out *out, const void *buffer, ssize_t read; uint32_t samples; int ret; - uint64_t time_us; - struct timespec anchor; + struct timespec current; + uint64_t audio_sent, audio_passed; + bool do_write = false; - time_us = ep->samples * 1000000ll / out->cfg.rate; + /* prepare media packet in advance so we don't waste time after + * wakeup + */ + mp->hdr.sequence_number = htons(ep->seq++); + mp->hdr.timestamp = htonl(ep->samples); + read = ep->codec->encode_mediapacket(ep->codec_data, + buffer + consumed, + bytes - consumed, mp, + free_space, &written); - timespec_add(&ep->start, time_us, &anchor); + /* not much we can do here, let's just ignore remaining + * data and continue + */ + if (read <= 0) + return true; - while (true) { - ret = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, - &anchor, NULL); + /* calculate where are we and where we should be */ + clock_gettime(CLOCK_MONOTONIC, ¤t); + if (!ep->samples) + memcpy(&ep->start, ¤t, sizeof(ep->start)); + audio_sent = ep->samples * 1000000ll / out->cfg.rate; + audio_passed = timespec_diff_us(¤t, &ep->start); - if (!ret) - break; + /* if we're ahead of stream then wait for next write point */ + if (audio_sent > audio_passed) { + struct timespec anchor; - if (ret != EINTR) { - error("clock_nanosleep failed (%d)", ret); - return false; + timespec_add(&ep->start, audio_sent, &anchor); + + while (true) { + ret = clock_nanosleep(CLOCK_MONOTONIC, + TIMER_ABSTIME, &anchor, + NULL); + + if (!ret) + break; + + if (ret != EINTR) { + error("clock_nanosleep failed (%d)", + ret); + return false; + } } } - read = ep->codec->encode_mediapacket(ep->codec_data, - buffer + consumed, - bytes - consumed, mp, - free_space, &written); - - /* This is non-fatal and we can just assume buffer was processed - * properly and wait for next one. + /* wait some time for socket to be ready for write, + * but we'll just skip writing data if timeout occurs */ - if (read <= 0) - return true; - - consumed += read; + if (!wait_for_endpoint(ep, &do_write)) + return false; - mp->hdr.sequence_number = htons(ep->seq++); - mp->hdr.timestamp = htonl(ep->samples); + if (do_write) + if (!write_to_endpoint(ep, written)) + return false; /* AudioFlinger provides 16bit PCM, so sample size is 2 bytes - * multipled by number of channels. Number of channels is simply - * number of bits set in channels mask. + * multiplied by number of channels. Number of channels is + * simply number of bits set in channels mask. */ samples = read / (2 * popcount(out->cfg.channels)); ep->samples += samples; - - while (true) { - ret = write(ep->fd, mp, sizeof(*mp) + written); - - if (ret >= 0) - break; - - if (errno != EINTR) - return false; - } + consumed += read; } return true; -- 1.9.2