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-rw-r--r--Documentation/sound/alsa/Procfile.txt5
-rw-r--r--sound/core/pcm_lib.c36
2 files changed, 40 insertions, 1 deletions
diff --git a/Documentation/sound/alsa/Procfile.txt b/Documentation/sound/alsa/Procfile.txt
index 381908d8ca42..719a819f8cc2 100644
--- a/Documentation/sound/alsa/Procfile.txt
+++ b/Documentation/sound/alsa/Procfile.txt
@@ -101,6 +101,8 @@ card*/pcm*/xrun_debug
bit 0 = Enable XRUN/jiffies debug messages
bit 1 = Show stack trace at XRUN / jiffies check
bit 2 = Enable additional jiffies check
+ bit 3 = Log hwptr update at each period interrupt
+ bit 4 = Log hwptr update at each snd_pcm_update_hw_ptr()
When the bit 0 is set, the driver will show the messages to
kernel log when an xrun is detected. The debug message is
@@ -117,6 +119,9 @@ card*/pcm*/xrun_debug
buggy) hardware that doesn't give smooth pointer updates.
This feature is enabled via the bit 2.
+ Bits 3 and 4 are for logging the hwptr records. Note that
+ these will give flood of kernel messages.
+
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 333e4dd29450..72cfd47af6b8 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -233,6 +233,18 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
xrun(substream);
return -EPIPE;
}
+ if (xrun_debug(substream, 8)) {
+ char name[16];
+ pcm_debug_name(substream, name, sizeof(name));
+ snd_printd("period_update: %s: pos=0x%x/0x%x/0x%x, "
+ "hwptr=0x%lx, hw_base=0x%lx, hw_intr=0x%lx\n",
+ name, (unsigned int)pos,
+ (unsigned int)runtime->period_size,
+ (unsigned int)runtime->buffer_size,
+ (unsigned long)old_hw_ptr,
+ (unsigned long)runtime->hw_ptr_base,
+ (unsigned long)runtime->hw_ptr_interrupt);
+ }
hw_base = runtime->hw_ptr_base;
new_hw_ptr = hw_base + pos;
hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;
@@ -244,18 +256,27 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
delta = new_hw_ptr - hw_ptr_interrupt;
}
if (delta < 0) {
- delta += runtime->buffer_size;
+ if (runtime->periods == 1 || new_hw_ptr < old_hw_ptr)
+ delta += runtime->buffer_size;
if (delta < 0) {
hw_ptr_error(substream,
"Unexpected hw_pointer value "
"(stream=%i, pos=%ld, intr_ptr=%ld)\n",
substream->stream, (long)pos,
(long)hw_ptr_interrupt);
+#if 1
+ /* simply skipping the hwptr update seems more
+ * robust in some cases, e.g. on VMware with
+ * inaccurate timer source
+ */
+ return 0; /* skip this update */
+#else
/* rebase to interrupt position */
hw_base = new_hw_ptr = hw_ptr_interrupt;
/* align hw_base to buffer_size */
hw_base -= hw_base % runtime->buffer_size;
delta = 0;
+#endif
} else {
hw_base += runtime->buffer_size;
if (hw_base >= runtime->boundary)
@@ -344,6 +365,19 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
xrun(substream);
return -EPIPE;
}
+ if (xrun_debug(substream, 16)) {
+ char name[16];
+ pcm_debug_name(substream, name, sizeof(name));
+ snd_printd("hw_update: %s: pos=0x%x/0x%x/0x%x, "
+ "hwptr=0x%lx, hw_base=0x%lx, hw_intr=0x%lx\n",
+ name, (unsigned int)pos,
+ (unsigned int)runtime->period_size,
+ (unsigned int)runtime->buffer_size,
+ (unsigned long)old_hw_ptr,
+ (unsigned long)runtime->hw_ptr_base,
+ (unsigned long)runtime->hw_ptr_interrupt);
+ }
+
hw_base = runtime->hw_ptr_base;
new_hw_ptr = hw_base + pos;