rtems_message_queue_receive / rtems_event_receive issues

[Mingyu Li]

Hi Catalin.

I find the problem you encountered interesting. I hope to offer some hints
that might be helpful to you:

1. use a user task to first rtems_event_send then rtems_event_receive, in
order to make sure the internal IPC of RTEMS kernel you are using (4.11.2)
works as expected.
2. ensure to disable/lock interrupts while operating the message_queue inside
USB ISR. Try to check if clock ISR is still responded when USB ISR exits,
so that the kernel task can be scheduled to obtain the message.

Best regards,
Mingyu

2018-09-18 20:20 GMT+08:00 Catalin Demergian <demergian at gmail.com>:

> Hello,
> I am using RTEMS 4.11.2 and I tried first to use RTEMS message queues in
> my USB FS driver.
> I'm populating the queue from the ISR and then use
> rtems_message_queue_receive from a kernel task to
> read the messages. After some debugging sessions I came to the conlusion
> that rtems_message_queue_receive function
> hangs even if there are messages in the queue. (manpage says it should
> return immediately if there is at least one message
> in the queue; in my case the queue gets full, but still the function hangs)
>
> I tried then rtems_event_receive. I used my own queues and from ISR I only
> called rtems_event_send; the same issue
> happened again, this time rtems_event_receive hangs even if I see the
> event was raised (with task command in the shell)
>
> My question is: are there any known issues/bugs with these functions ?
>
> thanks,
> Catalin
>
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