Commit 8bea869c authored by Jaroslav Kysela's avatar Jaroslav Kysela Committed by Takashi Iwai
Browse files

ALSA: PCM midlevel: improve fifo_size handling 



Move the fifo_size assignment to hw->ioctl callback to allow lowlevel
drivers overwrite the default behaviour.

fifo_size is in frames not bytes as specified in asound.h and alsa-lib's
documentation, but most hardware have fixed byte based FIFOs. Introduce
internal SNDRV_PCM_INFO_FIFO_IN_FRAMES.

Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent e93721a7

include/sound/asound.h

+1 −0
Original line number Diff line number Diff line
@@ -255,6 +255,7 @@ typedef int __bitwise snd_pcm_subformat_t; 
#define SNDRV_PCM_INFO_HALF_DUPLEX	0x00100000	/* only half duplex */

#define SNDRV_PCM_INFO_JOINT_DUPLEX	0x00200000	/* playback and capture stream are somewhat correlated */

#define SNDRV_PCM_INFO_SYNC_START	0x00400000	/* pcm support some kind of sync go */

#define SNDRV_PCM_INFO_FIFO_IN_FRAMES	0x80000000	/* internal kernel flag - FIFO size is in frames */



typedef int __bitwise snd_pcm_state_t;

#define	SNDRV_PCM_STATE_OPEN		((__force snd_pcm_state_t) 0) /* stream is open */

include/sound/pcm.h

+1 −0
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ struct snd_pcm_ops { 
#define SNDRV_PCM_IOCTL1_INFO		1

#define SNDRV_PCM_IOCTL1_CHANNEL_INFO	2

#define SNDRV_PCM_IOCTL1_GSTATE		3

#define SNDRV_PCM_IOCTL1_FIFO_SIZE	4



#define SNDRV_PCM_TRIGGER_STOP		0

#define SNDRV_PCM_TRIGGER_START		1

sound/core/pcm_lib.c

+19 −0
Original line number Diff line number Diff line
@@ -1524,6 +1524,23 @@ static int snd_pcm_lib_ioctl_channel_info(struct snd_pcm_substream *substream, 
	return 0;

}



static int snd_pcm_lib_ioctl_fifo_size(struct snd_pcm_substream *substream,

				       void *arg)

{

	struct snd_pcm_hw_params *params = arg;

	snd_pcm_format_t format;

	int channels, width;



	params->fifo_size = substream->runtime->hw.fifo_size;

	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_FIFO_IN_FRAMES)) {

		format = params_format(params);

		channels = params_channels(params);

		width = snd_pcm_format_physical_width(format);

		params->fifo_size /= width * channels;

	}

	return 0;

}



/**

 * snd_pcm_lib_ioctl - a generic PCM ioctl callback

 * @substream: the pcm substream instance
@@ -1545,6 +1562,8 @@ int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream, 
		return snd_pcm_lib_ioctl_reset(substream, arg);

	case SNDRV_PCM_IOCTL1_CHANNEL_INFO:

		return snd_pcm_lib_ioctl_channel_info(substream, arg);

	case SNDRV_PCM_IOCTL1_FIFO_SIZE:

		return snd_pcm_lib_ioctl_fifo_size(substream, arg);

	}

	return -ENXIO;

}

sound/core/pcm_native.c

+12 −3
Original line number Diff line number Diff line
@@ -312,9 +312,18 @@ int snd_pcm_hw_refine(struct snd_pcm_substream *substream, 


	hw = &substream->runtime->hw;

	if (!params->info)

		params->info = hw->info;

	if (!params->fifo_size)

		params->fifo_size = hw->fifo_size;

		params->info = hw->info & ~SNDRV_PCM_INFO_FIFO_IN_FRAMES;

	if (!params->fifo_size) {

		if (snd_mask_min(&params->masks[SNDRV_PCM_HW_PARAM_FORMAT]) ==

		    snd_mask_max(&params->masks[SNDRV_PCM_HW_PARAM_FORMAT]) &&

                    snd_mask_min(&params->masks[SNDRV_PCM_HW_PARAM_CHANNELS]) ==

                    snd_mask_max(&params->masks[SNDRV_PCM_HW_PARAM_CHANNELS])) {

			changed = substream->ops->ioctl(substream,

					SNDRV_PCM_IOCTL1_FIFO_SIZE, params);

			if (params < 0)

				return changed;

		}

	}

	params->rmask = 0;

	return 0;

}

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