Commit ead4046b authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Takashi Iwai
Browse files

ALSA: pcm: fix the fix of the runtime->boundary calculation 

Commit 7910b4a1 in 2.6.34 changed the
runtime->boundary calculation to make this value a multiple of both the
buffer_size and the period_size, because the latter is assumed by the
runtime->hw_ptr_interrupt calculation.

However, due to the lack of a ioctl that could read the software
parameters before they are set, the kernel requires that alsa-lib
calculates the boundary value, too.  The changed algorithm leads to
a different boundary value used by alsa-lib, which makes, e.g., mplayer
fail to play a 44.1 kHz file because the silence_size parameter is now
invalid; bug report:
<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5015

>.

This patch reverts the change to the boundary calculation, and instead
fixes the hw_ptr_interrupt calculation to be period-aligned regardless
of the boundary value.

Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 7f06a8b2

sound/core/pcm_lib.c

+7 −2
Original line number Diff line number Diff line
@@ -439,8 +439,13 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream, 
		snd_pcm_playback_silence(substream, new_hw_ptr);



	if (in_interrupt) {

		runtime->hw_ptr_interrupt = new_hw_ptr -

				(new_hw_ptr % runtime->period_size);

		delta = new_hw_ptr - runtime->hw_ptr_interrupt;

		if (delta < 0)

			delta += runtime->boundary;

		delta -= (snd_pcm_uframes_t)delta % runtime->period_size;

		runtime->hw_ptr_interrupt += delta;

		if (runtime->hw_ptr_interrupt >= runtime->boundary)

			runtime->hw_ptr_interrupt -= runtime->boundary;

	}

	runtime->hw_ptr_base = hw_base;

	runtime->status->hw_ptr = new_hw_ptr;

sound/core/pcm_native.c

+3 −36
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 
#include <linux/pm_qos_params.h>

#include <linux/uio.h>

#include <linux/dma-mapping.h>

#include <linux/math64.h>

#include <sound/core.h>

#include <sound/control.h>

#include <sound/info.h>
@@ -370,38 +369,6 @@ static int period_to_usecs(struct snd_pcm_runtime *runtime) 
	return usecs;

}



static int calc_boundary(struct snd_pcm_runtime *runtime)

{

	u_int64_t boundary;



	boundary = (u_int64_t)runtime->buffer_size *

		   (u_int64_t)runtime->period_size;

#if BITS_PER_LONG < 64

	/* try to find lowest common multiple for buffer and period */

	if (boundary > LONG_MAX - runtime->buffer_size) {

		u_int32_t remainder = -1;

		u_int32_t divident = runtime->buffer_size;

		u_int32_t divisor = runtime->period_size;

		while (remainder) {

			remainder = divident % divisor;

			if (remainder) {

				divident = divisor;

				divisor = remainder;

			}

		}

		boundary = div_u64(boundary, divisor);

		if (boundary > LONG_MAX - runtime->buffer_size)

			return -ERANGE;

	}

#endif

	if (boundary == 0)

		return -ERANGE;

	runtime->boundary = boundary;

	while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size)

		runtime->boundary *= 2;

	return 0;

}



static int snd_pcm_hw_params(struct snd_pcm_substream *substream,

			     struct snd_pcm_hw_params *params)

{
@@ -477,9 +444,9 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream, 
	runtime->stop_threshold = runtime->buffer_size;

	runtime->silence_threshold = 0;

	runtime->silence_size = 0;

	err = calc_boundary(runtime);

	if (err < 0)

		goto _error;

	runtime->boundary = runtime->buffer_size;

	while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size)

		runtime->boundary *= 2;



	snd_pcm_timer_resolution_change(substream);

	runtime->status->state = SNDRV_PCM_STATE_SETUP;

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