В Пн, 26/02/2024 в 13:05 +0000, Ian Malone пишет: > Hi, > > In short I have a USB to 3.5mm adapter which seems not to work in > duplex mode on USB2.0 systems, possibly due to a bandwidth > calculation > bug. > > This is an evolution of an issue I previously posted on the users > list > with no luck. I have an Anker USB-C to 3.5mm audio dongle (lsusb: > Conexant Systems (Rockwell), Inc. Hi-Res Audio) which I've used for > some time on my phone (Android with USB-3.2). On trying to use it > with > an older T420 laptop recently with only USB-2.0 ports I discovered it > will not work in duplex mode. Input-only and output-only profiles > work > (tested recording and playback with audacity), but with duplex no > sound is recorded (Fedora 39, pipewire). This is easily reproduced by > looking at the pavucontrol volume monitor for Output Devices, if I > switch the device to Analog or Digital Input in configuration then > the > Input Devices level monitor for it shows activity if I speak into or > tap the microphone. With duplex selected there is no activity, the > level monitor bar may or may not display. I can switch between the > two > behaviours by changing the profile. Various applications such as > Audacity and Zoom appear to hang when accessing this microphone with > the duplex profile set. I've used pipewire configuration to force the > format to 16LE only (playback and recording), but this has not > helped. > > In dmesg this error appears when this happens (microphone opened, for > example by pavucontrol): > [ 294.825544] usb 1-1.1: cannot submit urb 0, error -28: not enough > bandwidth > (T420, Fedora 39, kernel 6.7.5) Sorry, I somehow misread the first part of an email and was under impression that the problem is only with xhci host controller. Here I can only add that I have a system with the same "6 Series/C200 Series" chipset where I cannot reproduce this issue. But my full-speed card has a lower wMaxPacketSize.
