On Wed, 2 Apr 2003, Abramo Bagnara wrote:
Jaroslav Kysela ha scritto:
On Tue, 1 Apr 2003, Abramo Bagnara wrote:
I agree with Jaroslav fully:
- have one ALSA control for each primitive hw control (1536 different controls)
- add a field to struct sndrv_ctl_elem_info explaining how index field of sndvr_ctl_elem_id should be interpreted (32,16+16,10+11+11, ecc.)
This permit to have native support for N dimensional control.
About kernel memory issues, this concerns easily solvable implementation detail to not worry about when designing sane API.
Ok, I've added the dimension description to the info structure. Although it is completely irrelevant to data transfers.
Also, I've implemented multi element in the kernel space to save memory and it makes the searching faster. The reference code is in the trident driver. I'll recode other drivers containing many "same" controls to use this method later.
The lack of sparse matrix support I see in your implementation is a very unfortunate design choice.
I suggest you to use an hash table pointing to a pair { kcontrol_index, kcontrol_volatile_index } (16+16 should be enough) for control id searching and to move index info into snd_kcontrol_volatile_t.
I don't understand. The matrix is simply mapped to linear space. There is no requirement to do something special.
Perhaps I'm beginning to understand: you're using ordinary access for first N-1 dimensions and snd_kcontrol_volatile_t only for last dimension and only for contiguous values of index.
I believe this is not the right approach and linear search on a large number of controls should be avoided (because not scalable).
Also suppose to have a 10*10 control matrix but for each row but #3 you don't have a control for column #2, #4 and #6.
With your solution you still need to have 4*9+1=37 separate but identical snd_kcontrol_t instead of 1 if you adopt the solution I propose.
-- Abramo Bagnara mailto:[EMAIL PROTECTED]
Opera Unica Phone: +39.546.656023 Via Emilia Interna, 140 48014 Castel Bolognese (RA) - Italy
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