Hi,
On May 4 2016 22:59, Charles Keepax wrote:
We can't return a negative error code from the poll callback the return type is unsigned and is checked against the poll specific flags we need to return POLLERR if we encounter an error.
Signed-off-by: Charles Keepax ckeepax@opensource.wolfsonmicro.com
sound/core/pcm_native.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 9106d8e..c61fd50 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -3161,7 +3161,7 @@ static unsigned int snd_pcm_playback_poll(struct file *file, poll_table * wait)
substream = pcm_file->substream; if (PCM_RUNTIME_CHECK(substream))
return -ENXIO;
return POLLOUT | POLLWRNORM | POLLERR;runtime = substream->runtime;
poll_wait(file, &runtime->sleep, wait);
@@ -3200,7 +3200,7 @@ static unsigned int snd_pcm_capture_poll(struct file *file, poll_table * wait)
substream = pcm_file->substream; if (PCM_RUNTIME_CHECK(substream))
return -ENXIO;
return POLLIN | POLLRDNORM | POLLERR;runtime = substream->runtime;
poll_wait(file, &runtime->sleep, wait);
I agree with the concept of your patch to fix the return value of ALSA PCM core. It should return a value which consists of POLLxxx masks.
On the other hand, I think POLLOUT, POLLIN, POLLWRNORM and POLLRDNORM should not be included in the value. PCM_RUNTIME_CHECK() ensures PCM substream or PCM runtime is NULL. This means that subsequent I/O operations are failed, at least for handling PCM frames.
I think it better to return 'POLLERR | POLLHUP'.
Regards
Takashi Sakamoto