Hi, try to replay packets with a constant value like zero, you shouldn't hear any noise then, try to vary with the packet size, and maybe use USBSnoop for determining that (at least I was able to clearly determine what's going on..) I have no serious experience with other USB sniffers, I just used others but the outputs weren't as easy readable as with USBSnoop. Somehow I think we exactly have the same problem (but I almost solved my one..) Do all packets have the same packetsize? My USB Device varies with that too.. After exactly 46 seconds I get some buzz too with my device at the moment :( I couldn't determine any sync stuff there yet.. though I haven't correctly implemented the record feature correctly yet which might affect the other part as well .. let's see.. On 8/11/06, Stefano D'Angelo <zanga.mail@xxxxxxxxx> wrote: > Markus: I use USB Snoopy Pro and I'm sure that packet sizes are ok, I'm just > trying to do as the Windows' driver does. > > Clemens: > > No USB device supports DMA transfers. USB devices support USB transfers. > > The host controller supports DMA transfers. Yours does, too. I thought so too it sound kinda strange... > Well, I thought so. But I even modified snd-usb-audio driver (quirks + other > code) to support this card and what I get out of it is the same thing I got > when I tried with DMA on my own: a kind of buzz sound that sometimes > continues after stopping the playback. wrong device setup. > As you can see from the code I posted I'm not going this way, I'm copying > the data from runtime->dma_area into the URB transfer_buffer I allocate. > you have to do this anyway?! runtime->dma_area is alsa specific, and transfer_buffer is USB specific > > You should copy the data just before you submit the URB. In other words, > > yes. > I copy and send in the same function, is it right? > > > How do you determine how much data to send in each USB frame? > I use fixed sizes (as the windows' driver do). In snd_toneport.h each size > is specified according to the different altsettings. Each URB has 2 isoch. > packets of the same size. could you also provide a 20 MB USBSnoop (not usb snoopy) logfile (please zip it somewhere) cheers, Markus ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
