On Thu, 8 May 2014, Russel Hughes wrote: > Hi, > > Some more information from someone who has the same DAC as me and > has got it working on USB3.0 under Linux. I dont know if this helps > with a workround or just points to some fundamental problem with the > Intel hardware. > > "I was right in that MDAC works for me on USB3.0 (detected as NEC > uPD720200, Asus P8Z68 Deluxe motherboard), using xhci_hcd on a > more-or-less vanilla 3.12.3 kernel (yeah, I should upgrade soon): Have you also tried 3.12.3, to verify that the very same kernel gives different results on different hardware, and that the changes between 3.12 and 3.14 aren't responsible for the problem? > Code: > > # lsusb -t > ... > /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M > |__ Port 1: Dev 3, If 0, Class=HID, Driver=usbhid, 12M > |__ Port 1: Dev 3, If 1, Class=audio, Driver=snd-usb-audio, 12M > |__ Port 1: Dev 3, If 2, Class=audio, Driver=snd-usb-audio, 12M > ... > > Manually watching /proc/interrupts confirms that it's not going > through ehci_hcd. > > I can even play 24/96k without any problems (unlike unpatched ehci_hcd). > > Therfore your issue is either not xhci_hcd related, or is > hardware-specific. Make sure to mention your USB3 xhci controller in > that lkml thread." This does seem to point to an incompatibility between the driver and the Intel xHCI hardware. Figuring out what that incompability is may not be easy, though... Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
