[alsa-devel] xhci: Not enough bandwidth for new device state

[Clemens Ladisch]

Waldemar Brodkorb wrote:
>> [  547.352746] usb 3-5.2: 3:1: usb_set_interface failed (-28)
>> [  548.352865] usb 3-5.3: Not enough bandwidth for new device state.
>> [  548.352868] usb 3-5.3: Not enough bandwidth for altsetting 1
>>
>> I have connected a 7-Port USB 3.0 Hub to my machine.
>> I have 6 different Headsets and USB Soundcards connected to the HUB.
>>
>> As soon as I start a C++ application which opens all ALSA devices
>> I get these errors and the USB stopps working correctly.
>>
>> I think the maximum count of USB sound devices, which behave stable
>> is three or four.
>>
>> Is this some miscalculation of the Linux kernel regarding the USB
>> bandwidth usage? How I can determine how much bandwidth the USB
>> sound card driver preallocates?
>>
>> Or are five USB soundcards really too much for an USB 3.0 bus?
>
> There is no webcam involved, which usually uses MaxPacketsize of 1024,
> so why I get the overallocation?

AFAIK on xHCI controllers, the kernel and the controller's firmware
must work together to handle this.

It's possible that a USB 2.0 hub might work better.

Try asking on the linux-usb list.


Regards,
Clemens