ALSA: pcm: Add xrun_injection proc entry

This patch adds a new proc entry for PCM substreams to inject an
XRUN.  When a PCM substream is running and any value is written to its
xrun_injection proc file, the driver triggers XRUN.  This is a useful
feature for debugging XRUN and error handling code paths.

Note that this entry is enabled only when CONFIG_SND_PCM_XRUN_DEBUG is
set.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/sound/alsa/Procfile.txt b/Documentation/sound/alsa/Procfile.txt
index cfc49567b9dc..7f8a0d325905 100644
--- a/Documentation/sound/alsa/Procfile.txt
+++ b/Documentation/sound/alsa/Procfile.txt
@@ -133,6 +133,10 @@ card*/pcm*/sub*/sw_params
 card*/pcm*/sub*/prealloc
         The buffer pre-allocation information.
 
+card*/pcm*/sub*/xrun_injection
+        Triggers an XRUN to the running stream when any value is
+        written to this proc file.  Used for fault injection.
+        This entry is write-only.
 
 AC97 Codec Information
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