Just adding a brief explanation to alsa-configuration.rst.
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
Documentation/sound/alsa-configuration.rst | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst
index 392875a1b94e..72f97d4b01a7 100644
--- a/Documentation/sound/alsa-configuration.rst
+++ b/Documentation/sound/alsa-configuration.rst
@@ -2234,6 +2234,19 @@ use_vmalloc
buffers. If mmap is used on such architectures, turn off this
option, so that the DMA-coherent buffers are allocated and used
instead.
+delayed_register
+ The option is needed for devices that have multiple streams
+ defined in multiple USB interfaces. The driver may invoke
+ registrations multiple times (once per interface) and this may
+ lead to the insufficient device enumeration.
+ This option receives an array of strings, and you can pass
+ ID:INTERFACE like ``0123abcd:4`` for performing the delayed
+ registration to the given device. In this example, when a USB
+ device 0123:abcd is probed, the driver waits the registration
+ until the USB interface 4 gets probed.
+ The driver prints a message like "Found post-registration device
+ assignment: 1234abcd:04" for such a device, so that user can
+ notice the need.
This module supports multiple devices, autoprobe and hotplugging.
--
2.16.4
