From c8de6dbbbb422030d3c174146b2137e69a528d69 Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Fri, 25 Apr 2014 22:44:53 +0900 Subject: [PATCH 12/61] ALSA: firewire-lib: Restrict calling flush_context_completion() when context exists Currently, drivers can bring XRUN state for PCM substreams when error to queue packets or detecting discontinuity of packet. The application may try to recover this state by calling snd_pcm_prepare(). Depending on each driver, .prepare() includes restart streaming. Then there is a state that PCM substreams are running but isochronous contexts are stopped. In this case, when .pointer() is called, it refers to error pointer. This commit is for a prevention of this bug. Signed-off-by: Takashi Sakamoto Signed-off-by: Takashi Iwai --- sound/firewire/amdtp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c index ac8c35830cd9..7c814ace9e58 100644 --- a/sound/firewire/amdtp.c +++ b/sound/firewire/amdtp.c @@ -898,7 +898,7 @@ EXPORT_SYMBOL(amdtp_stream_start); unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s) { /* this optimization is allowed to be racy */ - if (s->pointer_flush) + if (s->pointer_flush && amdtp_stream_running(s)) fw_iso_context_flush_completions(s->context); else s->pointer_flush = true; -- 1.8.5.5