@@ -1250,6 +1250,24 @@ static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
urb_ctx_queue_advance(subs, urb, queued);
}
+/* copy bit-reversed bytes onto transfer buffer */
+static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
+ struct urb *urb, unsigned int bytes)
+{
+ struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+ const u8 *src = runtime->dma_area;
+ u8 *buf = urb->transfer_buffer;
+ int i, ofs = subs->hwptr_done;
+
+ for (i = 0; i < bytes; i++) {
+ *buf++ = bitrev8(src[ofs]);
+ if (++ofs >= subs->buffer_bytes)
+ ofs = 0;
+ }
+
+ urb_ctx_queue_advance(subs, urb, bytes);
+}
+
static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
int offset, int stride, unsigned int bytes)
{
@@ -1360,15 +1378,7 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
fill_playback_urb_dsd_dop(subs, urb, bytes);
} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
subs->cur_audiofmt->dsd_bitrev)) {
- /* bit-reverse the bytes */
- u8 *buf = urb->transfer_buffer;
- for (i = 0; i < bytes; i++) {
- int idx = (subs->hwptr_done + i) % subs->buffer_bytes;
-
- buf[i] = bitrev8(runtime->dma_area[idx]);
- }
-
- urb_ctx_queue_advance(subs, urb, bytes);
+ fill_playback_urb_dsd_bitrev(subs, urb, bytes);
} else {
/* usual PCM */
if (!subs->tx_length_quirk)
Just minor code refactoring. Like DOP DSD code, it can be better in a separate function for code readability. Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/usb/pcm.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-)