Re: [libusb] libusb Asynchronous Bulk Transfer Timeout On Linux Ubuntu

[Chris D. <chr...@gm...>]

In Linux, most error conditions are communicated through a negative return
value.

Cancelling an URB on Linux is done by unlinking it (
http://elixir.free-electrons.com/linux/v4.13/source/drivers/usb/core/devio.c#L1808).
When the URB is killed, the status passed is ENOENT (
http://elixir.free-electrons.com/linux/v4.13/source/drivers/usb/core/urb.c#L667
).

On Wed, Sep 13, 2017 at 10:06 AM, Ian Murtaugh <ian...@gm...>
wrote:

> Tim,
>
> The negative (-) throws me off, but I guess there is some sort of reverse
> mapping going on at the lower levels... ?
>
> Thanks,
> Ian
>
> On Wed, Sep 13, 2017 at 12:35 PM, Tim Roberts <ti...@pr...> wrote:
>
>> Ian Murtaugh wrote:
>> >
>> > Where is the URB status of a -2 defined?  I could NOT find it.
>>
>> My apologies for blindly forwarding someone else's answer instead of
>> looking it up.  URB status codes, like most kernel responses, are errno
>> values.  -2 is ENOENT, which generically means something was not found.
>> In this case, the generic kernel USB driver looked up endpoint ordinal 2
>> in its list of "output" endpoints, and there was no such entry.  ENOENT.
>>
>> --
>> Tim Roberts, ti...@pr...
>> Providenza & Boekelheide, Inc.
>>
>>
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>
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