From: Takashi Sakamoto Date: Fri, 2 Feb 2018 05:44:35 +0000 (+0900) Subject: pcm: fix a bug to copy silent samples aligned to 64 X-Git-Tag: v1.1.6~15 X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=36decd209f1b8683d4529911205d6f50612df349;p=alsa-lib.git pcm: fix a bug to copy silent samples aligned to 64 bits for 24 bit sample cases A function of 'snd_pcm_area_silence()' has a fast path to copy silent data efficiently. However, the fast path works well just for a case that target buffer consists of data samples for which unit of data alignment is divisors of 64 bits. At present, the fast path handles sample data aligned to 24 bit. In this case, the buffer can includes extra 8 bits. This has no issue for 'signed' case because silent data is zero, however it has an issue for 'unsigned' case. This commit fixes the bug by skipping cases of sample data of 24 bit. Signed-off-by: Takashi Sakamoto Signed-off-by: Jaroslav Kysela --- diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index 1753cdac..86250970 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -2947,7 +2947,11 @@ int snd_pcm_area_silence(const snd_pcm_channel_area_t *dst_area, snd_pcm_uframes dst = snd_pcm_channel_area_addr(dst_area, dst_offset); width = snd_pcm_format_physical_width(format); silence = snd_pcm_format_silence_64(format); - if (dst_area->step == (unsigned int) width) { + /* + * Iterate copying silent sample for sample data aligned to 64 bit. + * This is a fast path. + */ + if (dst_area->step == (unsigned int) width && (64 % width) == 0) { unsigned int dwords = samples * width / 64; uint64_t *dstp = (uint64_t *)dst; samples -= dwords * 64 / width;