ALSA: Update description of snd_card_create() in documents (d453379b) · Commits · EulixOS / Software / Kernel

Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl

+25 −19

Original line number	Diff line number	Diff line
		@@ -492,9 +492,9 @@
		}

		/* (2) */
		card = snd_card_new(index[dev], id[dev], THIS_MODULE, 0);
		if (card == NULL)
		return -ENOMEM;
		err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
		if (err < 0)
		return err;

		/* (3) */
		err = snd_mychip_create(card, pci, &chip);
		@@ -590,8 +590,9 @@
		<programlisting>
		<![CDATA[
		struct snd_card *card;
		int err;
		....
		card = snd_card_new(index[dev], id[dev], THIS_MODULE, 0);
		err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
		]]>
		</programlisting>
		</informalexample>
		@@ -809,26 +810,28 @@

		<para>
		As mentioned above, to create a card instance, call
		<function>snd_card_new()</function>.
		<function>snd_card_create()</function>.

		<informalexample>
		<programlisting>
		<![CDATA[
		struct snd_card *card;
		card = snd_card_new(index, id, module, extra_size);
		int err;
		err = snd_card_create(index, id, module, extra_size, &card);
		]]>
		</programlisting>
		</informalexample>
		</para>

		<para>
		The function takes four arguments, the card-index number, the
		The function takes five arguments, the card-index number, the
		id string, the module pointer (usually
		<constant>THIS_MODULE</constant>),
		and the size of extra-data space. The last argument is used to
		the size of extra-data space, and the pointer to return the
		card instance. The extra_size argument is used to
		allocate card->private_data for the
		chip-specific data. Note that these data
		are allocated by <function>snd_card_new()</function>.
		are allocated by <function>snd_card_create()</function>.
		</para>
		</section>

		@@ -915,15 +918,16 @@
		</para>

		<section id="card-management-chip-specific-snd-card-new">
		<title>1. Allocating via <function>snd_card_new()</function>.</title>
		<title>1. Allocating via <function>snd_card_create()</function>.</title>
		<para>
		As mentioned above, you can pass the extra-data-length
		to the 4th argument of <function>snd_card_new()</function>, i.e.
		to the 4th argument of <function>snd_card_create()</function>, i.e.

		<informalexample>
		<programlisting>
		<![CDATA[
		card = snd_card_new(index[dev], id[dev], THIS_MODULE, sizeof(struct mychip));
		err = snd_card_create(index[dev], id[dev], THIS_MODULE,
		sizeof(struct mychip), &card);
		]]>
		</programlisting>
		</informalexample>
		@@ -952,8 +956,8 @@

		<para>
		After allocating a card instance via
		<function>snd_card_new()</function> (with
		<constant>NULL</constant> on the 4th arg), call
		<function>snd_card_create()</function> (with
		<constant>0</constant> on the 4th arg), call
		<function>kzalloc()</function>.

		<informalexample>
		@@ -961,7 +965,7 @@
		<![CDATA[
		struct snd_card *card;
		struct mychip *chip;
		card = snd_card_new(index[dev], id[dev], THIS_MODULE, NULL);
		err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
		.....
		chip = kzalloc(sizeof(*chip), GFP_KERNEL);
		]]>
		@@ -5750,8 +5754,9 @@ struct _snd_pcm_runtime {
		....
		struct snd_card *card;
		struct mychip *chip;
		int err;
		....
		card = snd_card_new(index[dev], id[dev], THIS_MODULE, NULL);
		err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
		....
		chip = kzalloc(sizeof(*chip), GFP_KERNEL);
		....
		@@ -5763,7 +5768,7 @@ struct _snd_pcm_runtime {
		</informalexample>

		When you created the chip data with
		<function>snd_card_new()</function>, it's anyway accessible
		<function>snd_card_create()</function>, it's anyway accessible
		via <structfield>private_data</structfield> field.

		<informalexample>
		@@ -5775,9 +5780,10 @@ struct _snd_pcm_runtime {
		....
		struct snd_card *card;
		struct mychip *chip;
		int err;
		....
		card = snd_card_new(index[dev], id[dev], THIS_MODULE,
		sizeof(struct mychip));
		err = snd_card_create(index[dev], id[dev], THIS_MODULE,
		sizeof(struct mychip), &card);
		....
		chip = card->private_data;
		....