Attachment 316695 Details for Bug 462200 – Workaround patch for alsa-lib

[patch] Workaround patch for alsa-lib

alsa-lib-1.0.17-pcm-nonmonotonic-hwptr.patch (text/plain), 1.87 KB, created by Alexander Gavrilov on 2008-09-14 19:26:43 UTC

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Creator: Alexander Gavrilov

Created: 2008-09-14 19:26:43 UTC

Size: 1.87 KB

patch

obsolete

>From 5219d33e7754b8d45c1e951135c30c0c7a5bf86b Mon Sep 17 00:00:00 2001
>From: Alexander Gavrilov <angavrilov@gmail.com>
>Date: Sun, 14 Sep 2008 21:13:36 +0400
>Subject: [PATCH] Work around non-monotonic hw.ptr in the kernel driver.
>
>Fedora 9 with kernel 2.6.26.3-29 exhibits a bug where
>the driver decrements its hw.ptr under certain stress
>conditions, or at least it appears so from debugging.
>
>It causes alsa-lib to give absurdly huge avail numbers
>to pulseaudio, which crashes it. This patch adds a
>work-around to avoid such unfriendly behavior until
>the bug is fixed.
>
>As this is not a real fix, it displays a message every
>time it is activated.
>
>Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
>---
> src/pcm/pcm_local.h |    13 +++++++++++--
> 1 files changed, 11 insertions(+), 2 deletions(-)
>
>diff --git a/src/pcm/pcm_local.h b/src/pcm/pcm_local.h
>index b118f4b..63b893e 100644
>--- a/src/pcm/pcm_local.h
>+++ b/src/pcm/pcm_local.h
>@@ -415,8 +415,15 @@ static inline snd_pcm_uframes_t snd_pcm_mmap_playback_avail(snd_pcm_t *pcm)
> {
> 	snd_pcm_sframes_t avail;
> 	avail = *pcm->hw.ptr + pcm->buffer_size - *pcm->appl.ptr;
>-	if (avail < 0)
>+	if (avail < -(snd_pcm_sframes_t)(pcm->boundary/2))
> 		avail += pcm->boundary;
>+	else if (avail < 0) {
>+		static snd_pcm_sframes_t last_val = 0;
>+		if (avail != last_val)
>+			SNDERR("Playback backtrack detected: %i", avail);
>+		last_val = avail;
>+		avail = 0;
>+	}
> 	else if ((snd_pcm_uframes_t) avail >= pcm->boundary)
> 		avail -= pcm->boundary;
> 	return avail;
>@@ -455,8 +457,10 @@ static inline snd_pcm_sframes_t snd_pcm_mmap_hw_avail(snd_pcm_t *pcm)
> 	avail = *pcm->hw.ptr - *pcm->appl.ptr;
> 	if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
> 		avail += pcm->buffer_size;
>-	if (avail < 0)
>+	if (avail < -(snd_pcm_sframes_t)(pcm->boundary/2))
> 		avail += pcm->boundary;
>+	else if (avail < 0)
>+		avail = 0;
> 	return pcm->buffer_size - avail;
> }
> 
>-- 
>1.6.0.20.g6148bc
>

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