Introduce snd_pcm_lib_frames_to_timespec64() to replace the calculation
audio_nsecs = div_u64(audio_frames * 1000000000LL,
runtime->rate);
which overflows after a playback duration of 4.8 days @ 44100 HZ or 0.56
days @ 384000 Hz.
The implementation of snd_pcm_lib_frames_to_timespec64() extends these
limits, to 1.5 million years (@ 384000 Hz), or the 68 year limit of
struct timespec on 32-bit systems.
Fixes: 3179f6200188 ("ALSA: core: add .get_time_info")
Fixes: 4eeaaeaea1ce ("ALSA: core: add hooks for audio timestamps")
Signed-off-by: consult.awy@xxxxxxxxx
Suggested-by: Jaroslav Kysela <perex@xxxxxxxx>
Reviewed-by: Jaroslav Kysela <perex@xxxxxxxx>
---
sound/core/pcm_lib.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 943f5396fc60..e0a6556d33ee 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -205,12 +205,19 @@ int snd_pcm_update_state(struct snd_pcm_substream *substream,
return 0;
}
+static inline void snd_pcm_lib_frames_to_timespec64(u64 frames, unsigned int rate, struct timespec64 *audio_tstamp)
+{
+ u32 remainder;
+ audio_tstamp->tv_sec = div_u64_rem(frames, rate, &remainder);
+ audio_tstamp->tv_nsec = div_u64(mul_u32_u32(remainder, NSEC_PER_SEC), rate);
+}
+
static void update_audio_tstamp(struct snd_pcm_substream *substream,
struct timespec64 *curr_tstamp,
struct timespec64 *audio_tstamp)
{
struct snd_pcm_runtime *runtime = substream->runtime;
- u64 audio_frames, audio_nsecs;
+ u64 audio_frames;
struct timespec64 driver_tstamp;
if (runtime->tstamp_mode != SNDRV_PCM_TSTAMP_ENABLE)
@@ -233,9 +240,7 @@ static void update_audio_tstamp(struct snd_pcm_substream *substream,
else
audio_frames += runtime->delay;
}
- audio_nsecs = div_u64(audio_frames * 1000000000LL,
- runtime->rate);
- *audio_tstamp = ns_to_timespec64(audio_nsecs);
+ snd_pcm_lib_frames_to_timespec64(audio_frames, runtime->rate, audio_tstamp);
}
if (runtime->status->audio_tstamp.tv_sec != audio_tstamp->tv_sec ||
--
2.31.1
