On Wed, Aug 31, 2016 at 03:18:47PM +0100, Charles Keepax wrote:
On Wed, Aug 31, 2016 at 03:24:31PM +0200, Clemens Ladisch wrote:
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?)
Certainly tinyalsa does:
https://github.com/tinyalsa/tinyalsa/commit/45b2d047b8c2f4d9d1d87244f7f981db...
I thought the Intel guys added support to amixer as well although I may have been mistaken about that. I will try to find some time to look at that a little more closely. I guess my main concern here was the "very hardware specific" the intention is not to require hardware specific user-space code to use these controls.
Note yet, unfortunately :(
I have been trying to do that for amixer. I should be able to complete at least before our uConf :)
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.
Yes but that metadata is just being used to transfer the actual data for the control in this case. Personally I would just expect that control to function the same way as any other binary control for the user, just it is >512 bytes. Different things happen on the back end but it would be nice if it felt the same to the person using it. Which is mostly the case though tinyalsa at the moment.
Thanks, Charles