Am 24.10.22 um 10:13 schrieb Marc-André Lureau:
Hi

On Mon, Oct 24, 2022 at 9:28 AM Volker Rümelin <vr_q...@t-online.de> wrote:

    Test if the audio subsystem can handle extreme up- and down-
    sampling ratios like 44100/1 and 1/44100. For some time these
    used to trigger QEMU aborts. The test was taken from
    https://gitlab.com/qemu-project/qemu/-/issues/71 where it was
    used to demonstrate a very different issue.

    Suggested-by: Marc-André Lureau <marcandre.lur...@redhat.com>
    Signed-off-by: Volker Rümelin <vr_q...@t-online.de>


Thanks for working on this

It seems to show something different though:
"
A bug was just triggered in audio_calloc
Save all your work and restart without audio
I am sorry
"

AUD_open_out() is called with audsettings: {freq = 1, nchannels = 2, fmt = AUDIO_FORMAT_S16, endianness = 0}

And that's it. Any idea?

Hi,

the scary message is expected and doesn't mean this qos-test failed. This is the currently not so silent 'the audio subsystem should (...) silently give up' case.

The noaudio backend uses a mixing-engine buffer size of 1024 audio frames and AUD_open_* tries to allocate memory for 1024/44100 = 0.0232 audio frames for the resample buffer in audio_pcm_sw_alloc_resources_*. This allocation fails and produces the scary message. The error is handled correctly and AUD_open_* returns NULL. AUD_read and AUD_write return early if this pointer is NULL and the audio frontend callback functions will also not be called because the audio_frontend_frames_* functions return 0 in this case.

If you would like to see the two tests fail, revert commit 0cbc8bd469 ("audio: remove abort() in audio_bug()") and rerun qos-test.

With best regards,
Volker



    ---
     tests/qtest/ac97-test.c | 40 +++++++++++++++++++++++++++++++++++++++-
     1 file changed, 39 insertions(+), 1 deletion(-)

    diff --git a/tests/qtest/ac97-test.c b/tests/qtest/ac97-test.c
    index 74103efdfa..ce25f1d588 100644
    --- a/tests/qtest/ac97-test.c
    +++ b/tests/qtest/ac97-test.c
    @@ -42,16 +42,54 @@ static void *ac97_create(void *pci_bus,
    QGuestAllocator *alloc, void *addr)
         return &ac97->obj;
     }

    +/*
    + * This is rather a test of the audio subsystem and not an AC97
    test. Test if
    + * the audio subsystem can handle a 44100/1 upsample ratio. With
    an audio
    + * mixing buffer size of 1024 audio frames, the audio subsystem
    should either
    + * generate 1024 output frames from 0.0232 input frames or
    silently give up.
    + */
    +static void ac97_playback_upsample(void *obj, void *data,
    QGuestAllocator *alloc)
    +{
    +    QAC97 *ac97 = obj;
    +    QPCIDevice *dev = &ac97->dev;
    +    QPCIBar bar0;
    +
    +    qpci_device_enable(dev);
    +    bar0 = qpci_iomap(dev, 0, NULL);
    +    qpci_io_writew(dev, bar0, 0x2c, 0x1);
    +}
    +
    +/*
    + * This test is similar to the playback upsample test. This time
    the audio
    + * subsystem should either generate 0.0232 audio frames from 1024
    input frames
    + * or silently give up.
    + */
    +static void ac97_record_downsample(void *obj, void *data,
    QGuestAllocator *alloc)
    +{
    +    QAC97 *ac97 = obj;
    +    QPCIDevice *dev = &ac97->dev;
    +    QPCIBar bar0;
    +
    +    qpci_device_enable(dev);
    +    bar0 = qpci_iomap(dev, 0, NULL);
    +    qpci_io_writew(dev, bar0, 0x32, 0x1);
    +}
    +
     static void ac97_register_nodes(void)
     {
         QOSGraphEdgeOptions opts = {
    -        .extra_device_opts = "addr=04.0",
    +        .extra_device_opts = "addr=04.0,audiodev=snd0",
    +        .after_cmd_line = "-audiodev none,id=snd0"
    + ",out.frequency=44100,in.frequency=44100",
         };
         add_qpci_address(&opts, &(QPCIAddress) { .devfn =
    QPCI_DEVFN(4, 0) });

         qos_node_create_driver("AC97", ac97_create);
         qos_node_produces("AC97", "pci-device");
         qos_node_consumes("AC97", "pci-bus", &opts);
    +
    +    qos_add_test("playback_upsample", "AC97",
    ac97_playback_upsample, NULL);
    +    qos_add_test("record_downsample", "AC97",
    ac97_record_downsample, NULL);
     }

     libqos_init(ac97_register_nodes);
-- 2.35.3




--
Marc-André Lureau


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