ALSA: pcm: fix the fix of the runtime->boundary calculation
Commit 7910b4a1db63fefc3d291853d33c34c5b6352e8e 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: Clemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 644c2bb..303ac04 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -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 @@
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 @@
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;