ALSA: hdspm - Enable 32 samples/period on RME RayDAT/AIO
Newer RME cards like RayDAT and AIO support 32 samples per period. This
value is encoded as {1,1,1} in the HDSP_LatencyMask bits in the control
register.
Since {1,1,1} is also the representation for 8192 samples/period on
older RME cards, we have to special case 32 samples and 32768 bytes
according to the actual card.
Signed-off-by: Adrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/rme9652/hdspm.c b/sound/pci/rme9652/hdspm.c
index 1a52a1a..92ac64c 100644
--- a/sound/pci/rme9652/hdspm.c
+++ b/sound/pci/rme9652/hdspm.c
@@ -1323,12 +1323,27 @@
spin_lock_irq(&s->lock);
- frames >>= 7;
- n = 0;
- while (frames) {
- n++;
- frames >>= 1;
+ if (32 == frames) {
+ /* Special case for new RME cards like RayDAT/AIO which
+ * support period sizes of 32 samples. Since latency is
+ * encoded in the three bits of HDSP_LatencyMask, we can only
+ * have values from 0 .. 7. While 0 still means 64 samples and
+ * 6 represents 4096 samples on all cards, 7 represents 8192
+ * on older cards and 32 samples on new cards.
+ *
+ * In other words, period size in samples is calculated by
+ * 2^(n+6) with n ranging from 0 .. 7.
+ */
+ n = 7;
+ } else {
+ frames >>= 7;
+ n = 0;
+ while (frames) {
+ n++;
+ frames >>= 1;
+ }
}
+
s->control_register &= ~HDSPM_LatencyMask;
s->control_register |= hdspm_encode_latency(n);