Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8ef9df55 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Takashi Iwai
Browse files

ALSA: Add support for wildcard msbits constraints 



Currently the msbits constraints requires to specify a specific sample
format width for which the constraint should be applied. But often the
number of most significant bits is not sample format specific, but rather a
absolute limit. E.g. the PCM interface might accept 32-bit and 24-bit
samples, but the DAC has a 16-bit resolution and throws away the LSBs. In
this case for both 32-bit and 24-bit format msbits should be set to 16. This
patch extends snd_pcm_hw_constraint_msbits() so that a wildcard constraint
can be setup that is applied for all formats with a sample width larger than
the specified msbits. Choosing the wildcard constraint is done by setting
the sample width parameter of the function to 0.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 19f52fae

sound/core/pcm_lib.c

+12 −1
Original line number Diff line number Diff line
@@ -1299,8 +1299,14 @@ static int snd_pcm_hw_rule_msbits(struct snd_pcm_hw_params *params, 
	int width = l & 0xffff;

	unsigned int msbits = l >> 16;

	struct snd_interval *i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);

	if (snd_interval_single(i) && snd_interval_value(i) == width)



	if (!snd_interval_single(i))

		return 0;



	if ((snd_interval_value(i) == width) ||

	    (width == 0 && snd_interval_value(i) > msbits))

		params->msbits = min_not_zero(params->msbits, msbits);



	return 0;

}
@@ -1311,6 +1317,11 @@ static int snd_pcm_hw_rule_msbits(struct snd_pcm_hw_params *params, 
 * @width: sample bits width

 * @msbits: msbits width

 *

 * This constraint will set the number of most significant bits (msbits) if a

 * sample format with the specified width has been select. If width is set to 0

 * the msbits will be set for any sample format with a width larger than the

 * specified msbits.

 *

 * Return: Zero if successful, or a negative error code on failure.

 */

int snd_pcm_hw_constraint_msbits(struct snd_pcm_runtime *runtime,