vexpress audio is garbled

Bug #977610 reported by Michael Hope on 2012-04-09
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Linaro QEMU

Bug Description

Audio is garbled when playing back OGG files on the vexpress-a9 model with the 20120409 hwpack and alip root filesystem.

To reproduce:
 * Build the versions listed below
 * Boot into XFCE
 * Open a terminal
 * sudo apt-get install vorbis-tools ubuntu-sounds
 * cd /usr/share/sounds/ubuntu/stereo
 * ogg123 system-ready.ogg
 * Hear something like an explosion on a Commodore 64

It's not white noise - there's some type of envelope there and it plays for roughly the right time. Note that the audio is single channel. The same sound played fine on OMAP3 a few months ago. The same command plays fine on the host.

 * Ubuntu Precise x86_64
 * qemu-linaro 2012.04
 * linaro-o-alip-tar-20120409-1.tar.gz
 * hwpack_linaro-lt-vexpress-a9_20120409-1_armel_supported.tar.gz

Configured with ../qemu-linaro-1.0.50-2012.04/configure --prefix=$PWD/../install --audio-drv-list=alsa,pa.

root@linaro-alip:~# uname -a
Linux linaro-alip 3.3.0-1800-linaro-lt-vexpress-a9 #0-Ubuntu SMP PREEMPT Mon Mar 19 11:49:54 UTC 2012 armv7l armv7l armv7l GNU/Linux

Peter Maydell (pmaydell) wrote :

Is this a regression from previous versions of qemu-linaro? I just retried with the old vexpress image and mpg123 which was the test case I had for the audio when we originally put it into qemu-linaro's vexpress model, and that still works fine with 2012.04. My guess is that either audio is broken on this image on h/w too or it's doing something new and different which we don't model.

Peter Maydell (pmaydell) wrote :

ogg123 system-ready.ogg also works OK on qemu-linaro 2012.04 and a vexpress image from the 1108 linaro release.

Michael Hope (michaelh1) wrote :

I tried the 11.10 hwpack with the current alip image and see similar garbled noise with ogg123 on ogg files, aplay on wav files, and mpg123 on a mp3 file. The same fault occurs from within XFCE and from the command line.

Michael Hope (michaelh1) wrote :

Pinged Ryan.

Ryan Harkin (ryanharkin) wrote :

I've tested sound on our Ubuntu and Android images for the 12.03 release and it works fine. So the driver works at the very least.

I tested it using "aplay somefile.wav" and "ogg123 somefile.ogg".

I've just downloaded ALIP (never used it before!) and aplay and ogg123 both work fine.

Michael Hope (michaelh1) wrote :

aplay on a mono .wav file with the 2012.05 QEMU, kernel, and alip image work. I didn't try the OGG file so it might be to do with the channels or mode.

Peter Maydell (pmaydell) wrote :

Sounds plausible -- I think the audio chip model in qemu only implements a pretty limited subset of the total available modes.

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