Hello, for whatever reason, various amateur radio products use the PCM2903B, PCM2904 and related USB audio chips. On a system with an Intel C610/X99 USB xHCI controller (rev 05), and recent (>4.18?) kernels, this seems to result in USB babble errors. I hacked up this little patch to allow much larger USB packet sizes (the device advertises wMaxPacketSize 192), but that does not appear to change anything: https://paste.centos.org/view/f49e6f42 Where should I start looking to see what is going wrong? The usbmon tool is not capturing whatever packet caused the babble error (no surprise there), so I am not quite sure what my next step should be. The audio layer also never seems to get packets larger than 192 bytes even with the larger max packet size in the snd_usb_endpoint struct, so I am guessing maybe the babble error can also be caused by something other than a too-large packet? Maybe a packet that was transmitted after too much of a delay? Is there something in the urb that can be hacked to allow much larger transfers, or delays in transfers?, and some way to capture what may be going on here? -- All Rights Reversed.
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