In current implementation of ALSA control core, list operation has a limitation to handle 16384 entries at once. This seems due to allocation in kernel space to copy data from user space.
With a commit 53e7bf452584 ("ALSA: control: Simplify snd_ctl_elem_list() implementation"), for the operation, ALSA control core copies data into user space directly. No need to care of kernel spaces anymore.
This commit purges the limitation. --- sound/core/control.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/sound/core/control.c b/sound/core/control.c index 47080da8451a..ecd358213b83 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -757,9 +757,7 @@ static int snd_ctl_elem_list(struct snd_card *card, return -EFAULT; offset = list.offset; space = list.space; - /* try limit maximum space */ - if (space > 16384) - return -ENOMEM; + down_read(&card->controls_rwsem); list.count = card->controls_count; list.used = 0;