[alsa-devel] Support for floating point controls?

[Jaroslav Kysela]

On Thu, 28 Jan 2010, Eliot Blennerhassett wrote:

> Greetings,
>
> some of our products now have control paramters that are 32 bit floating
> point values.
>
> I wonder if a patch implementing float ctl elements would be accepted?
>
> Note that the floats are not manipulated in the kernel at all, the
> values are just passed through from the hardware to userspace (?)

If hardware supports this format, I have no objections against this 
extension.

> Adding something like:
>
> #define	SNDRV_CTL_ELEM_TYPE_FLOAT	((__force snd_ctl_elem_type_t) 7)
>
> struct snd_ctl_elem_info {
> ...
>  union {
> 	struct {
> 		float min;		/* R: minimum value */
> 		float max;		/* R: maximum value */
> 		float step;		/* R: step (0 variable) */
> 	} float;
> ...
> }
>
> struct snd_ctl_elem_value {
>  union {
> 	union {
> 		float value[128];
> 	} float;

Looks good. Also, don't forget to add the support for this type to 
alsa-lib.


 					Jaroslav

-----
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.