ALSA: pcm - Fix delta calculation at boundary overlap
When the hw_ptr_interrupt reaches the boundary, it must check whether
the hw_base was already lapped and corret the delta value appropriately.
Also, rebasing the hw_ptr needs a correction because buffer_size isn't
always aligned to period_size.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 92ed6d8..063c675 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -221,8 +221,11 @@
new_hw_ptr = hw_base + pos;
hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;
delta = new_hw_ptr - hw_ptr_interrupt;
- if (hw_ptr_interrupt == runtime->boundary)
- hw_ptr_interrupt = 0;
+ if (hw_ptr_interrupt >= runtime->boundary) {
+ hw_ptr_interrupt %= runtime->boundary;
+ if (!hw_base) /* hw_base was already lapped; recalc delta */
+ delta = new_hw_ptr - hw_ptr_interrupt;
+ }
if (delta < 0) {
delta += runtime->buffer_size;
if (delta < 0) {
@@ -233,6 +236,8 @@
(long)hw_ptr_interrupt);
/* 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;
} else {
hw_base += runtime->buffer_size;