Currently, The fixed 512KB prealloc buffer size is too larger for tiny memory kernel (such as 16MB memory). This patch adds the module option "prealloc_buffer_size_kbytes" to specify prealloc buffer size.

It's suitable for cards which use the generic dmaengine pcm driver with no config.

Signed-off-by: Sugar Zhang sugar.zhang@rock-chips.com ---

Documentation/sound/alsa-configuration.rst | 9 +++++++++ sound/soc/soc-generic-dmaengine-pcm.c | 6 +++++- 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst index 65f6169..34888d4 100644 --- a/Documentation/sound/alsa-configuration.rst +++ b/Documentation/sound/alsa-configuration.rst @@ -100,6 +100,15 @@ amidi_map MIDI device number maps assigned to the 2st OSS device; Default: 1

+Module snd-soc-core +------------------- + +The soc core module. It is used by all ALSA card drivers. +It takes the following options which have global effects. + +prealloc_buffer_size_kbytes + Specify prealloc buffer size in kbytes (default: 512). + Common parameters for top sound card modules --------------------------------------------

diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c index 4aa48c7..c54c8ca 100644 --- a/sound/soc/soc-generic-dmaengine-pcm.c +++ b/sound/soc/soc-generic-dmaengine-pcm.c @@ -15,6 +15,10 @@

#include <sound/dmaengine_pcm.h>

+static unsigned int prealloc_buffer_size_kbytes = 512; +module_param(prealloc_buffer_size_kbytes, uint, 0444); +MODULE_PARM_DESC(prealloc_buffer_size_kbytes, "Preallocate DMA buffer size (KB)."); + /* * The platforms dmaengine driver does not support reporting the amount of * bytes that are still left to transfer. @@ -237,7 +241,7 @@ static int dmaengine_pcm_new(struct snd_soc_component *component, prealloc_buffer_size = config->prealloc_buffer_size; max_buffer_size = config->pcm_hardware->buffer_bytes_max; } else { - prealloc_buffer_size = 512 * 1024; + prealloc_buffer_size = prealloc_buffer_size_kbytes * 1024; max_buffer_size = SIZE_MAX; }