Re: [PATCH v3 3/3] usb: gadget: f_uac2: allow explicit channel count independent of channel mask

[sashiko-bot@kernel.org]

> The UAC2 gadget driver currently derives bNrChannels from the number
> of set bits in bmChannelConfig. Since the bmChannelConfig
> channel-location bitmap provides only 27 predefined channel locations,
> this limits playback and capture streams to 27 channels. UAC2 allows
> bNrChannels to specify up to 255 channels, including channels without
> predefined locations in bmChannelConfig.
> 
> Add ConfigFS p_channels and c_channels attributes to configure the
> playback and capture channel counts explicitly.  Preserve the existing
> p_chmask and c_chmask interface and semantics. The default value of
> zero for p_channels and c_channels continues to derive the channel count
> from the corresponding p_chmask and c_chmask.
> 
> When an explicit channel count and a nonzero channel mask are both
> specified, require the number of set bits in the mask to match the
> channel count. Partial channel-location assignments permitted by UAC2
> are therefore not supported. Additionally, reject Feature Unit
> configurations whose descriptor length would exceed the one-byte
> bLength field.
> 
> Signed-off-by: Kyle Farrell <kaf@nwlink.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261103211434.996135-1-kaf@nwlink.com?part=3