[FS#256] usb audio doesn't work - "no such device"

[LEDE Bugs]

The following task has a new comment added:

FS#256 - usb audio doesn't work - "no such device"
User who did this - Dmitry (f3flight)

----------
default size - 3972516
with flag - 16496700

That's quite an impact, unexpected I might say. However the squashfs firmware size is still the same size - 3.25MB.

Here is the git diff for the change - could you try on your system to confirm the size difference?
---------------------
diff --git a/target/linux/ramips/mt7620/config-4.4 b/target/linux/ramips/mt7620/config-4.4
index a2a7717..3e4be95 100644
--- a/target/linux/ramips/mt7620/config-4.4
+++ b/target/linux/ramips/mt7620/config-4.4
@@ -184,11 +184,15 @@ CONFIG_SCHED_HRTICK=y
 # CONFIG_SERIAL_8250_FSL is not set
 CONFIG_SERIAL_8250_RT288X=y
 CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_SND=m
+# CONFIG_SND_COMPRESS_OFFLOAD is not set
+CONFIG_SND_PCM_TIMER=y
 CONFIG_SOC_MT7620=y
 # CONFIG_SOC_MT7621 is not set
 # CONFIG_SOC_RT288X is not set
 # CONFIG_SOC_RT305X is not set
 # CONFIG_SOC_RT3883 is not set
+CONFIG_SOUND=m
 CONFIG_SPI=y
 CONFIG_SPI_MASTER=y
 # CONFIG_SPI_MT7621 is not set
--------------------

If we just add the flag in sound-core this won't be enough? Or it will impact kernel image size?

----------

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=256#comment771