[alsa-devel] [PATCH 2/5] ALSA: snd_usb_caiaq: give better shortname

[Takashi Iwai]

At Tue, 2 Jun 2009 11:31:04 +0200,
Daniel Mack wrote:
> 
> On Tue, Jun 02, 2009 at 09:49:39AM +0200, Takashi Iwai wrote:
> > > So what's your suggestion to fix the behaviour I was describing? Maybe a
> > > combination of Jaroslav's collision detection together with a logic that
> > > does not touch the id in case it was passed as module option?
> > 
> > Sounds reasonable.  We may need just a number suffix if any collision
> > occurs.
> 
> What about that patch below? Works well in my tests here.

Looks almost good, but we need to check
snd_info_check_reserved_words() too.

I guess the routine in choose_default_id() can be reused for this
function, though.

Jaroslav seems working on this now, so maybe he could better cope
with you...


Takashi


> 
> Daniel
> 
> 
> >From 7f7544af491f6073da3aea72c64f5725c50246c8 Mon Sep 17 00:00:00 2001
> From: Daniel Mack <daniel at caiaq.de>
> Date: Tue, 2 Jun 2009 11:23:41 +0200
> Subject: [PATCH] ALSA: introduce snd_card_make_id_unique()
> 
> Sound card drivers may choose their own way to provide a nice sound card
> ID, especially when the default behaviour taken by choose_default_name()
> is not appropriate. ALSA's IDs must be unique, so there is need for some
> core logic to ensure that.
> 
> This patch adds the function snd_card_make_id_unique() to the ALSA core
> which lowlevel drivers can call to make sure the computed string isn't
> already taken.
> 
> Signed-off-by: Daniel Mack <daniel at caiaq.de>
> Cc: Takashi Iwai <tiwai at suse.de>
> Cc: Jaroslav Kysela <perex at perex.cz>
> ---
>  include/sound/core.h |    1 +
>  sound/core/init.c    |   45 +++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 46 insertions(+), 0 deletions(-)
> 
> diff --git a/include/sound/core.h b/include/sound/core.h
> index 3dea798..01ea816 100644
> --- a/include/sound/core.h
> +++ b/include/sound/core.h
> @@ -319,6 +319,7 @@ int snd_card_info_done(void);
>  int snd_component_add(struct snd_card *card, const char *component);
>  int snd_card_file_add(struct snd_card *card, struct file *file);
>  int snd_card_file_remove(struct snd_card *card, struct file *file);
> +void snd_card_make_id_unique(struct snd_card *card);
>  
>  #ifndef snd_card_set_dev
>  #define snd_card_set_dev(card, devptr) ((card)->dev = (devptr))
> diff --git a/sound/core/init.c b/sound/core/init.c
> index fd56afe..8503a01 100644
> --- a/sound/core/init.c
> +++ b/sound/core/init.c
> @@ -547,6 +547,51 @@ static void choose_default_id(struct snd_card *card)
>  	}
>  }
>  
> +static int
> +card_id_is_ambiguous(struct snd_card *card, const char *id)
> +{
> +	int i;
> +
> +	for (i = 0; i < snd_ecards_limit; i++) {
> +		/* only run for exisiting cards but not for the
> +		 * one in question */
> +		if (i == card->number || !snd_cards[i])
> +			continue;
> +
> +		if (strcmp(snd_cards[i]->id, id) == 0)
> +			return 1;
> +	}
> +
> +	return 0;
> +}
> +
> +void
> +snd_card_make_id_unique(struct snd_card *card)
> +{
> +	int count = 1;
> +	char id[sizeof(card->id)];
> +
> +	if (*card->id == '\0')
> +		return;
> +
> +	strlcpy(id, card->id, sizeof(id));
> +
> +	while (card_id_is_ambiguous(card, id)) {
> +		/* As we need to add some characters to the id, make
> +		 * sure there's enough room for it */
> +		int maxlen = sizeof(card->id) - (2 + (count / 10));
> +
> +		if (strlen(card->id) > maxlen)
> +			card->id[maxlen] = '\0';
> +
> +		snprintf(id, sizeof(id), "%s_%d", card->id, count);
> +		count++;
> +	}
> +
> +	strlcpy(card->id, id, sizeof(id));
> +}
> +EXPORT_SYMBOL_GPL(snd_card_make_id_unique);
> +
>  #ifndef CONFIG_SYSFS_DEPRECATED
>  static ssize_t
>  card_id_show_attr(struct device *dev,
> -- 
> 1.6.3.1
>