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_lib.c b/sound/core/pcm_lib.c
index a2ff861..22aff18 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -439,8 +439,13 @@
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;
