[pulseaudio-discuss] [PATCH 4/4] alsa-mixer: Attempt to detect and then drop redundant paths in the path set.

[David Henningsson]

On 2011-07-02 19:27, Colin Guthrie wrote:
> In order to try and avoid 'spamming' the user with port choices,
> attempt to detect and remove any redundant paths in a path set.

Hi Colin and thanks for working on this!

> This should solve a problem case with some USB Headsets which result in
> two paths both using the 'Speaker' element when no 'Master' element exists
> (and even in this case, one of those two paths wouldn't really work
> anyway due to not actually having h/w volume control due to the absense
> of 'Master')

Ehm, are you sure this is working? "Analog output" does not control 
"Speaker" whereas "Analog speaker" does, so how can they turn out to be 
equal in the code below?

> ---
>   src/modules/alsa/alsa-mixer.c |   46 +++++++++++++++++++++++++++++++++++++++++
>   1 files changed, 46 insertions(+), 0 deletions(-)
>
> diff --git a/src/modules/alsa/alsa-mixer.c b/src/modules/alsa/alsa-mixer.c
> index abd3bf2..ea5a49d 100644
> --- a/src/modules/alsa/alsa-mixer.c
> +++ b/src/modules/alsa/alsa-mixer.c
> @@ -2873,6 +2873,51 @@ void pa_alsa_path_set_dump(pa_alsa_path_set *ps) {
>           pa_alsa_path_dump(p);
>   }
>
> +static void path_set_condense(pa_alsa_path_set *ps) {
> +    pa_alsa_path *p1, *np1, *p2, *np2;
> +
> +    for (p1 = ps->paths; p1; p1 = np1) {
> +        np1 = p1->next;
> +
> +        for (p2 = p1->next; p2; p2 = np2) {
> +            pa_alsa_element *e1, *e2;
> +            pa_bool_t same = TRUE;
> +
> +            np2 = p2->next;
> +
> +            /* Compare the elements of each set... */
> +            pa_assert_se(e1 = p1->elements);
> +            pa_assert_se(e2 = p2->elements);
> +
> +            while (same) {
> +                if (pa_streq(e1->alsa_name, e2->alsa_name)&&  e1->switch_use == e2->switch_use) {
> +                    e1 = e1->next;
> +                    e2 = e2->next;
> +                    if ((e1&&  !e2) || (!e1&&  e2))
> +                        same = FALSE;
> +                    else if (!e1&&  !e2)
> +                        break;
> +                } else
> +                    same = FALSE;
> +            }
> +
> +            if (same) {
> +                pa_alsa_path *remove_path, *keep_path;
> +                if (p1->priority>= p2->priority) {
> +                    keep_path = p1;
> +                    remove_path = p2;
> +                } else {
> +                    keep_path = p2;
> +                    remove_path = p1;
> +                }
> +                pa_log_debug("Removing redundant path '%s' as it contains the same elements as '%s' which has higher priority.", remove_path->name, keep_path->name);
> +                PA_LLIST_REMOVE(pa_alsa_path, ps->paths, remove_path);
> +                pa_alsa_path_free(remove_path);
> +            }
> +        }
> +    }
> +}
> +
>   static void path_set_make_paths_unique(pa_alsa_path_set *ps) {
>       pa_alsa_path *p, *q;
>
> @@ -2928,6 +2973,7 @@ void pa_alsa_path_set_probe(pa_alsa_path_set *ps, snd_mixer_t *m, pa_bool_t igno
>           }
>       }
>
> +    path_set_condense(ps);
>       path_set_make_paths_unique(ps);
>       ps->probed = TRUE;
>   }


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