----- Mail original ----- > De: "Hans Wilmers" <hanswil@xxxxxxxxxx> > À: linux-audio-user@xxxxxxxxxxxxxxxxxxxx > Envoyé: Jeudi 10 Janvier 2013 23:23:56 > Objet: Re: Sound Devices USBPre2, UAC2 status > > On 01/10/2013 10:30 PM, shal@xxxxxxx wrote: > > > >> De: "Hans Wilmers" <hanswil@xxxxxxxxxx> > >> No luck with this either - fastest one I get is 48000. This > >> corresponds > >> to the output of lsusb, which does not list samplerates over 48000 > >> for > >> this device. > > > > > > I have tried different kernel, 3.2 to 3.7.1, vanilla or ubuntu > > kernel. > > > > The lsusb does not means that you are limited to 48000. > > > > The lsusb provides the "devices descriptor" and a devices > > descriptors has one or more "configuration descriptor". The kernel > > chooses one of the "configuration descriptor". > > In your device descriptor (provided directly by the device) there > > is two possibles configuration descriptons (the > > bNumConfigurations=2). The first one corresponds to the UAC1 mode > > in high-speed (this is my one configuration) and so limited to > > 48000. The second one is the UAC2 mode (the expected mode). > > > > Perhaps the kernel choose the fist good one, so UAC1 . > > > > Can you send the result of cat /proc/asound/USBPre2/stream0 ? > > > > Yes, see below. > > / Hans > > > --------------- /proc/asound/USBPre2/stream0 ------------- > > Sound Devices USBPre2 at usb-0000:00:1a.0-1.2, high speed : USB Audio > > Playback: > Status: Stop > Interface 1 > Altset 1 > Format: S16_LE > Channels: 2 > Endpoint: 6 OUT (ASYNC) > Rates: 8000, 16000, 24000, 32000, 44100, 48000 > Data packet interval: 1000 us > Interface 1 > Altset 2 > Format: S24_3LE > Channels: 2 > Endpoint: 6 OUT (ASYNC) > Rates: 8000, 16000, 24000, 32000, 44100, 48000 > Data packet interval: 1000 us Hi Hans, So , effectively you are limited to 48000. I supposed that the linux kernel chooses this first valid configuration descriptor. This behavior can be modified in the kernel with adding a quirk in the code. If my usbPre2 has the good device descripton, I can devlop and test this patch. But my devices does not offer the UAC2 configuration descriptor. I have write a post on the Sound Devices Forum. Perhaps I will have help to understand why my device has this strange behavior and correct it. In this case, I think I can patch the kernel to have the UAC2 mode... Olivier _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
