[ALSA] pcm core: add prealloc_max file to substream directory to show maximum DMA...

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/include/sound/pcm.h b/include/sound/pcm.h
index 016c418..ec006ed 100644 (file)
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -384,6 +384,7 @@ struct snd_pcm_substream {
        struct snd_info_entry *proc_sw_params_entry;
        struct snd_info_entry *proc_status_entry;
        struct snd_info_entry *proc_prealloc_entry;
+       struct snd_info_entry *proc_prealloc_max_entry;
 #endif
        /* misc flags */
        unsigned int hw_opened: 1;

diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index be030cb..95b1b2f 100644 (file)
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -101,6 +101,8 @@ int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
 {
        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
@@ -141,6 +143,18 @@ static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
        snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
 }
 
+/*
+ * 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
  *
@@ -203,6 +217,15 @@ static inline void preallocate_info_init(struct snd_pcm_substream *substream)
                }
        }
        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 */