Commit 2ceb65cd authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: Update the documentation for the new delayed_register option 

Just adding a brief explanation to alsa-configuration.rst.

Link: https://lore.kernel.org/r/20200325103322.2508-5-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent a4aad563

Documentation/sound/alsa-configuration.rst

+13 −0
Original line number Diff line number Diff line
@@ -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.

CRA Git | Maintained and supported by SUSTech CRA and CCSE