В Вт, 27/02/2024 в 21:27 +0300, Alexander Tsoy пишет: > В Пн, 26/02/2024 в 13:05 +0000, Ian Malone пишет: > > > ---------->%----------- > > In this case the dmesg output is clear after device connection. > > This > > seems like some kind of bandwidth calculation problem in > > snd_usb_audio. I've tried building a kernel and modifying various > > of > > the defines in sound/usb/card.h (currently MAX_PACKS 4 and > > MAX_PACKS_HS (MAX_PACKS * 4), compared to 6 and *8) but not hit on > > a > > winning formula yet. Is there any information I could collect to > > try > > to fix this? > > > > I always had bandwidth allocation problems with full-speed > isochronous > devices connected directly to xhci host controllers (and no other > devices connected!). The same devices works with ehci host > controllers > without issues. So I think the problem is somewhere in the xhci code. > > Also if device is connected to the hub which is connected to xhci > controller, everything also works. This is why rear ports works for > you > - they are connected to the internal hub. And this is because transaction translation is performed on the hub, so the controller is only dealing with high-speed transfers. BTW, I just tested all mentioned connection scenarios with Audiotrak Prodigy CUBE. And indeed I get "Not enough bandwidth" errors in duplex mode only if it is connected directly to xhci controller.
