[LAU] Teufel PC Bamster not getting connected on USB?

[David Kastrup]

Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw at public.gmane.org>
writes:

> David Kastrup wrote:
>> Clemens Ladisch writes:
>>> David Kastrup wrote:
>>>> I just got some older Bamster soundbar model (probably not a keeper)
>>>> that takes USB either for power (in which case it uses AUX in analog) or
>>>> also as USB soundcard.  In the latter case, however, it just switches
>>>> itself off after a few seconds.
>>>>
>>>> [ 1201.960192] usb 5-2: new full-speed USB device number 5 using uhci_hcd
>>>> [ 1203.344305] usbhid 5-2:1.3: can't add hid device: -71
>>>> [ 1203.456336] usb 5-2: USB disconnect, device number 5
>>>
>>> I'd guess that the firmware tries to detect if it is connect to an actaual
>>> PC (as opposed to some charger), and that Linux doesn't look right.
>>
>> You sure that it's the Bamster taking the initiative here?
>
> The host hardware is not capable of causing the "disconnect" message.

Well, I'll have to trust you on that.  Then perhaps one of the preceding
interactions that appear to have failed don't make the Bamster happy.

>> it sounds more like Linux does something bad here.  Should it respond
>> differently to any request?
>
> I guess the Bamster expects it to behave identical with the Windows driver.

I'll see what it does on some XP computer tomorrow.  Can't access it
right now.

I mean, this was a used sale.  Can also just be broken.  Or it talks
with the host and says "I want 1A of current or 2A" and the host says
"no way".  But it's delivered by default with a two-host-plug USB cable
and would not be able to know about the power available from the
power-only plug.  And it doesn't complain when running from the analog
input either, so it would be somewhat strange to just shut down when in
USB mode.

Any idea what I could be testing?

-- 
David Kastrup