----- Mail original ----- > De: "Hans Wilmers" <hanswil@xxxxxxxxxx> > À: linux-audio-user@xxxxxxxxxxxxxxxxxxxx > Envoyé: Jeudi 10 Janvier 2013 13:23:57 > Objet: Re: Sound Devices USBPre2, UAC2 status > > On 01/07/2013 08:25 PM, shal@xxxxxxx wrote: > > > > ----- Mail original ----- > >> De: "alexander" <axeldenstore@xxxxxxxxx> > >> À: linux-audio-user@xxxxxxxxxxxxxxxxxxxx > >> Envoyé: Lundi 7 Janvier 2013 18:27:42 > >> Objet: Re: Sound Devices USBPre2, UAC2 status > >> I also own this interface, recently it has started to work in uac2 > >> mode, > >> I still cant raise the samplerate, but it runs.. however, It still > >> runs > >> alot better in uac1.. when in uac2 jack mysteriously shuts down > >> for > >> no > >> appearant reason. I run archlinux, allways uptodated with vanilla > >> kernel. > >> > >> This is when I connect it without pressing 1. eg, uac2 > >> http://pastebin.com/BFJTwXnJ > >> And as with pressing 1. http://pastebin.com/ZJ1jbPUK > > > > > > Hi, > > > > In my understanding, you are not in UAC2 , you are in high-speed > > mode but the usb audio protocol remains UAC1. > > > > > > In the kernel source in the file include/uapi/linux/usb/audio.h is > > defined two values: > > /* bInterfaceProtocol values to denote the version of the standard > > used */ > > #define UAC_VERSION_1 0x00 > > #define UAC_VERSION_2 0x20 > > > > So if the card is in UAC2 , you should see bInterfaceProtocol at 32 > > (or 0x20) > > By example, now the RME babyface is recognize as UAC2 device, you > > can view its "lsub -v" here : http://minilien.fr/a0m3kc > > > > But for the usbPre2 device with ou without pressing the "1" button, > > we have bInterfaceProtocol = 0. So we stays in UAC1, even the > > speed increase to high-speed. > > > > I was also surprised to see that the USBPre2 now works duplex without > pressing the "1" button while connecting. > > This was tested on Fedora 17 with stock kernel 3.6.6-1.fc17. > Jack was set to 512 Frames/period and 3 periods/buffer, and in a 24h > recording I got no xruns. > I did not manage to choose a sample rate unlike 48000, though. > > With lsusb, I can see 2 configurations for the same device, and the > second one has bInterfaceProtocol = 32 for all interfaces except HID: > http://pastebin.com/zwq0VVbM Hi Hans, Thank you for provided information. So, some usbPre2 have bNumConfigurations=2 when "1" is not pressed but not all usbPre2 (mine or alexander devices have only one "Configuration Descriptor"). Your device descriptor contains a UAC2 configuration descriptor, This sound good. Perhaps there is different firmware ? I have the 1.03 firmware. Can you provide your firmware level ? Can you test 192khz value in jackd ? Olivier _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
