Scratchy playback issue with USB CLASS2 audio device

[Taner]

Hi,

I modified uaudio.c according to your patch but it didn't make any
difference. I'm running 10.0-stable. It doesn't matter with vchan
adaptive/fixed or bitperfect settings. Behavior is same. I don't know how
to read usbdump output thus I'm mailing 5 sec. playback output file to you
(1.5MB zipped). It captured while vchan at 16bit/48Khz.

I keen on any other suggestion from you. I don't know why but sound quality
is obviously better in FreeBSD despite this playback issue still remains.

Regards,
Taner


On Sat, Oct 19, 2013 at 9:42 AM, Hans Petter Selasky <hps at bitfrost.no>wrote:

> On 10/19/13 08:35, Hans Petter Selasky wrote:
>
>> On 10/19/13 07:46, Taner wrote:
>>
>>> uaudio_chan_play_sync_**callback: Value = 0x0005fff8
>>> uaudio_chan_play_sync_**callback: Comparing 47998 < 48000
>>> uaudio_chan_play_sync_**callback: Value = 0x0005fff6
>>> uaudio_chan_play_sync_**callback: Comparing 47998 < 48000
>>>
>>
>> Hi,
>>
>> The normal for adaptive rates is that this value should tilt just above
>> or below the 48000 or whatever is there. Else something is wrong.
>>
>> Did you try to record while playing?
>>
>> Also, are you running -stable?
>>
>> Could also check the amount of samples sent by using
>> "usbdump -i usbusX -f Y -s 65536 -vvv"
>>
>> --HPS
>>
>
> Hi,
>
> Does this patch make any difference?
>
> === dev/sound/usb/uaudio.c
> ==============================**==============================**======
> --- dev/sound/usb/uaudio.c      (revision 256754)
> +++ dev/sound/usb/uaudio.c      (local)
> @@ -2070,7 +2070,7 @@
>                 chn_intr(ch->pcm_ch);
>
>                 /* start SYNC transfer, if any */
> -               if ((ch->last_sync_time++ & 7) == 0)
> +               if ((ch->last_sync_time++ & 3) == 0)
>                         usbd_transfer_start(ch->xfer[**UAUDIO_NCHANBUFS]);
>
>         case USB_ST_SETUP:
>
> --HPS
>