On Mon, 31 Mar 2003, Giuliano Pochini wrote:
>
> On 31-Mar-2003 Jaroslav Kysela wrote:
> >> the case 2 is, IMO, the most straightforward way. the info field will
> >> have number of rows and columns, in addition to min, max and step
> >> values. the change in the alsa core wouldn't be too much.
> >
> > I think that we simply touch the barrier given by 'struct
> > sndrv_ctl_elem_id'. The identification which differentiate identical
> > controls is only the 'index' value. If we don't use 'struct
> > sndrv_ctl_elem_id' as the identification unit for read/writing of data,
> > then we end with trouble with notification and other representation
> > (single data unit locking, inactive flag etc). Imagine three or four
> > dimensional data types. [...]
>
> .count is an uint32. Ok, suppose we do not change it. Then the low
> level driver has to tell user space apps that the index number
> addresses elements in a W*H matrix, so the apps will locate the
> cell at (x,y) by a simple index=x+W*y.
Yes, except that the lowlevel driver won't tell that there is a matrix. It
can be indentified by element name (string) or by the description in the
user space. We decided to remove all mixer routing/connection/element
types (except the value types) information from the kernel space to
simplify drivers.
Jaroslav
-----
Jaroslav Kysela <[EMAIL PROTECTED]>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs
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