Return-Path: From: Andrei Emeltchenko To: linux-bluetooth@vger.kernel.org Subject: [RFCv0 01/14] android/hal-sco: Use nanosleep for SCO synchronization Date: Thu, 22 May 2014 15:05:54 +0300 Message-Id: <1400760367-24915-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: From: Andrei Emeltchenko --- android/hal-sco.c | 56 +++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 42 insertions(+), 14 deletions(-) diff --git a/android/hal-sco.c b/android/hal-sco.c index ea9857e..fb7b4d4 100644 --- a/android/hal-sco.c +++ b/android/hal-sco.c @@ -64,6 +64,8 @@ struct sco_stream_out { int fd; uint8_t *downmix_buf; + size_t samples; + struct timespec start; struct resampler_itfe *resampler; int16_t *resample_buf; @@ -277,6 +279,21 @@ static void downmix_to_mono(struct sco_stream_out *out, const uint8_t *buffer, } } +static uint64_t timespec_diff_us(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 += 1000000000ll; /* 1sec */ + } + + return res.tv_sec * 1000000ll + res.tv_nsec / 1000ll; +} + static bool write_data(struct sco_stream_out *out, const uint8_t *buffer, size_t bytes) { @@ -284,13 +301,13 @@ static bool write_data(struct sco_stream_out *out, const uint8_t *buffer, size_t len, written = 0; int ret; uint16_t mtu = /* out->cfg.mtu */ 48; - uint8_t read_buf[mtu]; - bool do_write = false; + uint64_t audio_sent_us, audio_passed_us; pfd.fd = out->fd; pfd.events = POLLOUT | POLLIN | POLLHUP | POLLNVAL; while (bytes > written) { + struct timespec now; /* poll for sending */ if (poll(&pfd, 1, SOCKET_POLL_TIMEOUT_MS) == 0) { @@ -303,27 +320,38 @@ static bool write_data(struct sco_stream_out *out, const uint8_t *buffer, return false; } - /* FIXME synchronize by time instead of read() */ - if (pfd.revents & POLLIN) { - ret = read(out->fd, read_buf, mtu); - if (ret < 0) { - error("Error reading fd %d (%s)", out->fd, - strerror(errno)); - return false; - } - do_write = true; + clock_gettime(CLOCK_REALTIME, &now); + /* Mark start of the stream */ + if (!out->samples) + memcpy(&out->start, &now, sizeof(out->start)); + + audio_sent_us = out->samples * 1000000ll / AUDIO_STREAM_SCO_RATE; + audio_passed_us = timespec_diff_us(&now, &out->start); + if ((int) (audio_sent_us - audio_passed_us) > 1500) { + struct timespec timeout = {0, + (audio_sent_us - + audio_passed_us) * 1000}; + DBG("Sleeping for %d ms", + (int) (audio_sent_us - audio_passed_us)); + nanosleep(&timeout, NULL); + } else if ((int)(audio_passed_us - audio_sent_us) > 50000) { + DBG("\n\nResync\n\n"); + out->samples = 0; + memcpy(&out->start, &now, sizeof(out->start)); } - if (!do_write) - continue; len = bytes - written > mtu ? mtu : bytes - written; ret = write(out->fd, buffer + written, len); if (ret > 0) { written += ret; - do_write = false; + + out->samples += ret / 2; + + DBG("written %d samples %zd total %zd bytes", + ret, out->samples, written); continue; } -- 1.8.3.2