On 03. 05. 23 22:19, Oswald Buddenhagen wrote:
On Wed, May 03, 2023 at 01:20:37PM +0200, Oswald Buddenhagen wrote:
On Tue, May 02, 2023 at 01:50:07PM +0200, Jaroslav Kysela wrote:
+ * or the next period wake up)
+ */
+ sw_params.silence_threshold = pcm->buffer_size;
+ sw_params.silence_size = silence_size;
so at this point i got the thought "huh, that can exceed the buffer
size. is that ok?" ...
and yes, it is. but ...
the kernel doesn't check silence_threshold, so user space can trigger
the snd_BUG_ON() in snd_pcm_playback_silence(). whoops.
(yes, this predates my patch.)
i'm not sure what the best way to deal with this is. anyway, different
tree, different patch.
actually, that analysis is garbage, because i didn't look at enough
context. :}
the kernel _does_ check the values in snd_pcm_sw_params(), which means
that silence_size exceeding silence_threshold would lead to EINVAL, and
therefore silencing being broken. this will inevitably happen with small
buffer sizes, where the 1/10th sec extension dominates.
Yes, I overlooked this. Thanks. Fixed in:
https://github.com/alsa-project/alsa-lib/commit/58077e2f0d896ff848f3551518b1d9fc6c97d695
Jaroslav
--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
