Commit 2e610270 authored by Adrian Knoth's avatar Adrian Knoth Committed by Takashi Iwai
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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: default avatarAdrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 7cb155ff
......@@ -1323,12 +1323,27 @@ static int hdspm_set_interrupt_interval(struct hdspm *s, unsigned int frames)
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);
......
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