ALSA: usb-audio: move and add some comments
Also add a list of open topics.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index ba54eb6..1163ec3 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -26,6 +26,22 @@
*
*/
+/*
+ * TODOs, for both the mixer and the streaming interfaces:
+ *
+ * - support for UAC2 effect units
+ * - support for graphical equalizers
+ * - RANGE and MEM set commands (UAC2)
+ * - RANGE and MEM interrupt dispatchers (UAC2)
+ * - audio channel clustering (UAC2)
+ * - audio sample rate converter units (UAC2)
+ * - proper handling of clock multipliers (UAC2)
+ * - dispatch clock change notifications (UAC2)
+ * - stop PCM streams which use a clock that became invalid
+ * - stop PCM streams which use a clock selector that has changed
+ * - parse available sample rates again when clock sources changed
+ */
+
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/list.h>
@@ -1199,14 +1215,6 @@
}
} else { /* UAC_VERSION_2 */
for (i = 0; i < 30/2; i++) {
- /* From the USB Audio spec v2.0:
- bmaControls() is a (ch+1)-element array of 4-byte bitmaps,
- each containing a set of bit pairs. If a Control is present,
- it must be Host readable. If a certain Control is not
- present then the bit pair must be set to 0b00.
- If a Control is present but read-only, the bit pair must be
- set to 0b01. If a Control is also Host programmable, the bit
- pair must be set to 0b11. The value 0b10 is not allowed. */
unsigned int ch_bits = 0;
unsigned int ch_read_only = 0;
