Tim,
If I call the same code with one thread, it works without any problem. so I
believe it has something to do with how libusb work in multi-threading code.
Do you have any sample code how to handle multi-threading for libusb
asynchronous operations? do I need to anything to protect call to
libusb_handle_events_timeout_completed ? (can
libusb_handle_events_timeout_completed
be call at same time from multiple thread?)
Did I do anything wrong in the loop? anything I am suppose to do I did not
do in code?
I pretty much showed you the whole libusb related code here, the only thing
I did not show is the client, which is very complicated and I am not sure
how it was related to this libusb problem.
The bottom line is I got a client spawn multiple threads, calling my code,
one BulkRead, one BulkWrite, in both function, it has the
same identical loop as following:
while (!userdata->ExitTransfer)
{
//I also added Lock here for the whole block here and
to serialize the call to
//libusb_handle_events_timeout_completed, but it still does not work.
struct timeval tv = { 1, 0 };
int completed =0;
err = libusb_handle_events_timeout_completed(NULL, &tv,&completed );
}
Also from the trace, "what does no URB with timeout or all handled by OS;
no timeout!" mean?
233.648362] [000024bc] libusbx: debug [libusb_get_next_timeout] no URB with
timeout or all handled by OS; no timeout!
[233.651362] [000024bc] libusbx: debug
[libusb_handle_events_timeout_completed] doing our own event handling
[233.651362] [000024bc] libusbx: debug [handle_events] poll() 2 fds with
timeout in 1000ms
[234.658463] [000024bc] libusbx: debug [handle_events] poll() returned 0
15BulkRead call libusb_handle_events_timeout,completed value is 0; Error
Code is 0
[234.707468] [000024bc] libusbx: debug [libusb_get_next_timeout] no URB
with timeout or all handled by OS; no timeout!
[234.709468] [000024bc] libusbx: debug
[libusb_handle_events_timeout_completed] doing our own event handling
[234.710468] [000024bc] libusbx: debug [handle_events] poll() 2 fds with
timeout in 1000ms
[235.716569] [000024bc] libusbx: debug [handle_events]
Please advice.
thx
On Wed, Sep 12, 2012 at 2:14 PM, Tim Roberts <t...@probo.com> wrote:
> John Chen wrote:
> > Tim, I attache the usb debug trace and USB_Trace here. Yes, I did get
> > a timeout, but if you look at USBTrace.txt, it have the following:
> >
> > [libusb_get_next_timeout] no URB with timeout or all handled by OS; no
> > timeout!
> > do you need what it means?
>
> It looks like you are running multiple simultaneous event loops. Is
> that correct? You don't need to do that. You can see how the log
> output is garbled, apparently because the log output is intermixed with
> another thread writing at the exact same time.
>
> My best guess is that you have some kind of multithreading problem, but
> there's not much we can do without seeing the whole code, and I'm not
> sure you really want to do that. You need to think about what order
> things are happening, remembering that asynchronous operations will
> always arrive at the most inconvenient time.
>
> --
> Tim Roberts, t...@probo.com
> Providenza & Boekelheide, Inc.
>
>
>
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