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usb: audio: correctly report internal delay

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Every USB device must buffer isochronous data for at least 1 frame in
order to remove packet jitter within a frame. USB Specification Revision
2.0 describes necessary buffering in 5.12.5 Data Prebuffering. USB Audio
1.0 specification mentions buffering in 3.4 Inter Channel Synchronization.

Set bDelay to 1 instead of 0, because bDelay 1 is both the minimum
allowed value and matches the actual device behavior.

Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>
This commit is contained in:
Tomasz Moń 2023-07-18 11:26:54 +02:00 • committed by Alberto Escolar
commit e47fc45c4d
1 changed files with 1 additions and 1 deletions
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2
subsys/usb/device/class/audio/usb_audio_internal.h
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@ -473,7 +473,7 @@ struct dev##_descriptor_##i { \
.bDescriptorType = USB_DESC_CS_INTERFACE, \
.bDescriptorSubtype = USB_AUDIO_AS_GENERAL, \
.bTerminalLink = link, \
.bDelay = 0, \
.bDelay = 1, \
.wFormatTag = sys_cpu_to_le16(0x0001), \
}