Commit cedb8118 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: pcm - Add logging of hwptr updates and interrupt updates 



Added the logging functionality to xrun_debug to record the hwptr
updates via snd_pcm_update_hw_ptr() and snd_pcm_update_hwptr_interrupt(),
corresponding to 16 and 8, respectively.

For example,
	# echo 9 > /proc/asound/card0/pcm0p/xrun_debug
will record the position and other parameters at each period interrupt
together with the normal XRUN debugging.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 79452f0a

Documentation/sound/alsa/Procfile.txt

+5 −0
Original line number Diff line number Diff line
@@ -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.

sound/core/pcm_lib.c

+25 −0
Original line number Diff line number Diff line
@@ -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, pos,

			   (int)runtime->period_size,

			   (int)runtime->buffer_size,

			   (long)old_hw_ptr,

			   (long)runtime->hw_ptr_base,

			   (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;
@@ -353,6 +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, pos,

			   (int)runtime->period_size,

			   (int)runtime->buffer_size,

			   (long)old_hw_ptr,

			   (long)runtime->hw_ptr_base,

			   (long)runtime->hw_ptr_interrupt);

	}



	hw_base = runtime->hw_ptr_base;

	new_hw_ptr = hw_base + pos;

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