[pulseaudio-discuss] [PATCH 2/4] alsa-ucm: Don't probe UCM

[David Henningsson]

On 09/18/2013 07:41 PM, Felipe Tonello wrote:
> Hi David,
> 
> On Wed, Sep 18, 2013 at 7:01 AM, David Henningsson
> <david.henningsson at canonical.com> wrote:
>> In case of UCM, it usually targets a very specific hardware. The
>> person writing the UCM file for that hardware knows what (s)he is
>> doing, hopefully.
>>
>> Does it harm to probe all verbs at startup? Yes, because it can
>> cause longer startup time, clicks, or other side effects.
>>
>> (This is a difference to the normal probing mechanism, where we try
>> to make one profile set file fit many different sound cards, hence
>> we need probing there. But not here.)
>>
>> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
>> ---
>>  src/modules/alsa/alsa-ucm.c |    4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/modules/alsa/alsa-ucm.c b/src/modules/alsa/alsa-ucm.c
>> index 81d0aeb..ab23259 100644
>> --- a/src/modules/alsa/alsa-ucm.c
>> +++ b/src/modules/alsa/alsa-ucm.c
>> @@ -1367,6 +1367,7 @@ static int ucm_create_profile(
>>      return 0;
>>  }
>>
>> +#if 0
>>  static snd_pcm_t* mapping_open_pcm(pa_alsa_ucm_config *ucm, pa_alsa_mapping *m, int mode) {
>>      snd_pcm_t* pcm;
>>      pa_sample_spec try_ss = ucm->core->default_sample_spec;
>> @@ -1514,6 +1515,7 @@ static void ucm_probe_profile_set(pa_alsa_ucm_config *ucm, pa_alsa_profile_set *
>>
>>      pa_alsa_profile_set_drop_unsupported(ps);
>>  }
>> +#endif
>>
>>  pa_alsa_profile_set* pa_alsa_ucm_add_profile_set(pa_alsa_ucm_config *ucm, pa_channel_map *default_channel_map) {
>>      pa_alsa_ucm_verb *verb;
>> @@ -1539,7 +1541,7 @@ pa_alsa_profile_set* pa_alsa_ucm_add_profile_set(pa_alsa_ucm_config *ucm, pa_cha
>>          ucm_create_profile(ucm, ps, verb, verb_name, verb_desc);
>>      }
>>
>> -    ucm_probe_profile_set(ucm, ps);
>> +/*    ucm_probe_profile_set(ucm, ps); */
>>      ps->probed = true;
>>
>>      return ps;
> 
> Why not just remove the code?

This is just the first draft. We might end up with some way of
configuring whether to probe or not (suggestions welcome).


-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic