[ALSA] pcm core: add prealloc_max file to substream directory to show maximum DMA size
Users ask us many times about the maximum DMA size for PCM devices. This
file gives them a hint in KB.
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index be030cb..95b1b2f 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -101,6 +101,8 @@
{
snd_pcm_lib_preallocate_dma_free(substream);
#ifdef CONFIG_SND_VERBOSE_PROCFS
+ snd_info_free_entry(substream->proc_prealloc_max_entry);
+ substream->proc_prealloc_max_entry = NULL;
snd_info_free_entry(substream->proc_prealloc_entry);
substream->proc_prealloc_entry = NULL;
#endif
@@ -142,6 +144,18 @@
}
/*
+ * read callback for prealloc_max proc file
+ *
+ * prints the maximum allowed size in kB.
+ */
+static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
+ struct snd_info_buffer *buffer)
+{
+ struct snd_pcm_substream *substream = entry->private_data;
+ snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
+}
+
+/*
* write callback for prealloc proc file
*
* accepts the preallocation size in kB.
@@ -203,6 +217,15 @@
}
}
substream->proc_prealloc_entry = entry;
+ if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root)) != NULL) {
+ entry->c.text.read = snd_pcm_lib_preallocate_max_proc_read;
+ entry->private_data = substream;
+ if (snd_info_register(entry) < 0) {
+ snd_info_free_entry(entry);
+ entry = NULL;
+ }
+ }
+ substream->proc_prealloc_max_entry = entry;
}
#else /* !CONFIG_SND_VERBOSE_PROCFS */