The indirect-PCM helper codes have an implicit assumption that the appl_ptr always increases. But the PCM core may deal with the decrement of appl_ptr via rewind ioctls, and it may screw up the buffer pointer management.
This patch adds the negative appl_ptr diff in transfer functions and let returning an error instead of always accepting the appl_ptr updates. The callers are usually PCM ack callbacks, and they pass the error to the upper layer accordingly.
Signed-off-by: Takashi Iwai tiwai@suse.de --- include/sound/pcm-indirect.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/sound/pcm-indirect.h b/include/sound/pcm-indirect.h index 1df7acaaa535..7ade285328cf 100644 --- a/include/sound/pcm-indirect.h +++ b/include/sound/pcm-indirect.h @@ -43,7 +43,7 @@ typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream, /* * helper function for playback ack callback */ -static inline void +static inline int snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, struct snd_pcm_indirect *rec, snd_pcm_indirect_copy_t copy) @@ -56,6 +56,8 @@ snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, if (diff) { if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) diff += runtime->boundary; + if (diff < 0) + return -EINVAL; rec->sw_ready += (int)frames_to_bytes(runtime, diff); rec->appl_ptr = appl_ptr; } @@ -82,6 +84,7 @@ snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, rec->hw_ready += bytes; rec->sw_ready -= bytes; } + return 0; }
/* @@ -109,7 +112,7 @@ snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream, /* * helper function for capture ack callback */ -static inline void +static inline int snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, struct snd_pcm_indirect *rec, snd_pcm_indirect_copy_t copy) @@ -121,6 +124,8 @@ snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, if (diff) { if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) diff += runtime->boundary; + if (diff < 0) + return -EINVAL; rec->sw_ready -= frames_to_bytes(runtime, diff); rec->appl_ptr = appl_ptr; } @@ -147,6 +152,7 @@ snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, rec->hw_ready -= bytes; rec->sw_ready += bytes; } + return 0; }
/*