[alsa-devel] [PATCH 1/4] ALSA: control: return payload length for TLV operation

[Clemens Ladisch]

Charles Keepax wrote:
> On Wed, Aug 31, 2016 at 01:54:37PM +0200, Clemens Ladisch wrote:
>> Anyway, the separate length value could be useful only for drivers (like
>> soc-wm-adsp) that use a binary stream where TLV data should have been
>> used.  But the software that writes these coefficients to the WM ADSP
>> driver is very hardware specific anyway, and it presumably already works
>> without knowing the returned length value.  So there is no case where
>> this patchset _actually_ improves the interface.
>
> The software that writes these coefficients to wm_adsp is
> not hardware specific at all its just regular amixer and
> tinymix.

As far as I can see, neither amixer nor tinymix support writing
or "command"ing TLV data.  Do you mean alsactl or alsaucm?

(And I notice that when alsa-lib's UCM loads TLV data from a file,
it does check that the second word contains the correct size.  Is
this value also correct when reading TLV from these controls?)

> These TLV controls are just like any other ALSA control

You're treating it like one, but actually TLV is not a control type but
metadata attached to a control.


Regards,
Clemens