Bug 98674

Summary: Rewinding results in omitted samples
Product: PulseAudio Reporter: Kai Ruhnau <kai.ruhnau>
Component: alsaAssignee: pulseaudio-bugs
Status: RESOLVED MOVED QA Contact: pulseaudio-bugs
Severity: normal    
Priority: medium CC: lennart
Version: unspecified   
Hardware: ARM   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: Test tone
Full audio output
Truncated output 1
Truncated output 2

Description Kai Ruhnau 2016-11-10 15:17:44 UTC 
Created attachment 127891 [details]
Test tone

I'm running my Yocto distribution (morty with PulseAudio 9.0) with Linux 4.7 on an i.MX6SX platform containing a Wolfson WM9715 codec driven by the wm9712 driver.

I'm trying to play a small test wav file with about 100ms duration (see attachment). I can successfully use aplay on the hardware device directly.

When I use PulseAudio to play that file (for example through aplay or by upload-sample/play-sample), sometimes samples at the beginning are omitted and don't reach the analog audio output (see following attachments).

It doesn't happen if this is the first time something is played after the server has started. It then happens every time (with varying number of samples) until the alsa card is suspended. It then again doesn't happen once after the card is unsuspended.

After a small IRC session, I already have disabled the rewinding code (https://cgit.freedesktop.org/pulseaudio/pulseaudio/tree/src/modules/alsa/alsa-sink.c?id=8887f256e0f1167e579a217387a4efc5397edf93#n1649) and this makes the problem go away, but I'd be surprised if this was even close to an actual solution.
Comment 1 Kai Ruhnau 2016-11-10 15:18:21 UTC 
Created attachment 127892 [details]
Full audio output
Comment 2 Kai Ruhnau 2016-11-10 15:18:43 UTC 
Created attachment 127893 [details]
Truncated output 1
Comment 3 Kai Ruhnau 2016-11-10 15:19:05 UTC 
Created attachment 127894 [details]
Truncated output 2
Comment 4 GitLab Migration User 2018-07-30 10:02:18 UTC 
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/issues/179.

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