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authorTakashi Iwai <tiwai@suse.de>2009-05-27 10:53:33 +0200
committerTakashi Iwai <tiwai@suse.de>2009-05-27 11:04:30 +0200
commitc87d9732004b3f8fd82d729f12ccfb96c0df279e (patch)
treef265b35a8c34fa7d0bc41c46b519b330a4d68e8e
parent6af3fb72d2437239e5eb13a59e95dc43ccab3e8f (diff)
downloadop-kernel-dev-c87d9732004b3f8fd82d729f12ccfb96c0df279e.zip
op-kernel-dev-c87d9732004b3f8fd82d729f12ccfb96c0df279e.tar.gz
ALSA: Enable PCM hw_ptr_jiffies check only in xrun_debug mode
The PCM hw_ptr jiffies check results sometimes in problems when a hardware doesn't give smooth hw_ptr updates. So far, au88x0 and some other drivers appear not working due to this strict check. However, this check is a nice debug tool, and the capability should be still kept. Hence, we disable this check now as default unless the user enables it by setting the xrun_debug mode to the specific stream via a proc file. Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--Documentation/sound/alsa/Procfile.txt5
-rw-r--r--sound/core/pcm_lib.c9
2 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/sound/alsa/Procfile.txt b/Documentation/sound/alsa/Procfile.txt
index bba2dbb..cfac20c 100644
--- a/Documentation/sound/alsa/Procfile.txt
+++ b/Documentation/sound/alsa/Procfile.txt
@@ -104,6 +104,11 @@ card*/pcm*/xrun_debug
When this value is greater than 1, the driver will show the
stack trace additionally. This may help the debugging.
+ Since 2.6.30, this option also enables the hwptr check using
+ jiffies. This detects spontaneous invalid pointer callback
+ values, but can be lead to too much corrections for a (mostly
+ buggy) hardware that doesn't give smooth pointer updates.
+
card*/pcm*/sub*/info
The general information of this PCM sub-stream.
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 3eea98a..d659995 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -249,6 +249,11 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
new_hw_ptr = hw_base + pos;
}
}
+
+ /* Do jiffies check only in xrun_debug mode */
+ if (!xrun_debug(substream))
+ goto no_jiffies_check;
+
/* Skip the jiffies check for hardwares with BATCH flag.
* Such hardware usually just increases the position at each IRQ,
* thus it can't give any strange position.
@@ -336,7 +341,9 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
hw_base = 0;
new_hw_ptr = hw_base + pos;
}
- if (((delta * HZ) / runtime->rate) > jdelta + HZ/100) {
+ /* Do jiffies check only in xrun_debug mode */
+ if (xrun_debug(substream) &&
+ ((delta * HZ) / runtime->rate) > jdelta + HZ/100) {
hw_ptr_error(substream,
"hw_ptr skipping! "
"(pos=%ld, delta=%ld, period=%ld, jdelta=%lu/%lu)\n",
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