fread blocks on device data read?

João Rasta freakforever at gmail.com
Wed Aug 18 09:18:04 UTC 2010


I found out that the problem was that i was not assigning a unique pirq line
to the uart while building the LEON hardware project. It is working ok after
assigning a unique irq line.

Many thanks all.


Best,
JM



On Tue, Aug 17, 2010 at 5:13 PM, João Rasta <freakforever at gmail.com> wrote:

> read() is not working as well with the uart in interrupt mode. It blocks
> the same way as fread. I have set the termios parameters the same way as in
> the RTEMS version with the uarts in polling mode so this is not the cause.
> What can i be missing? Any suspicious configuration?
>
> I'm configuring RTEMS with
>
> #define CONFIGURE_INIT
> #define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
> #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
> #define CONFIGURE_NUMBER_OF_TERMIOS_PORTS           2
>
>
> #define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS    10
> #define CONFIGURE_POSIX_INIT_THREAD_STACK_SIZE        (10*1024)
> #define CONFIGURE_INIT_TASK_ATTRIBUTES                RTEMS_FLOATING_POINT
>
> #define CONFIGURE_MAXIMUM_POSIX_THREADS             10
> #define CONFIGURE_MAXIMUM_POSIX_MUTEXES                10
> #define CONFIGURE_MAXIMUM_POSIX_CONDITION_VARIABLES    8
> #define CONFIGURE_MAXIMUM_POSIX_SEMAPHORES            8
> #define CONFIGURE_MAXIMUM_POSIX_KEYS                5
> #define CONFIGURE_MAXIMUM_POSIX_TIMERS                5
> #define CONFIGURE_MAXIMUM_POSIX_QUEUED_SIGNALS        8
> #define CONFIGURE_MAXIMUM_POSIX_MESSAGE_QUEUES        8
>
>
>
> Best,
> JM
>
>
> On Tue, Aug 17, 2010 at 5:00 PM, Eric Norum <wenorum at lbl.gov> wrote:
>
>> On Aug 17, 2010, at 8:56 AM, João Rasta wrote:
>>
>> > You mean setting termios struct and use tcsetattr() to set the
>> parameters? tcsetattr() only accepts the file descriptor ID as an int, not a
>> FILE * pointer which is returned by fopen()..
>>
>> Right.
>> In many cases you're better off using the low level open/read/write calls
>> with serial ports anyway since the buffering performed by the stdio routines
>> just gets in the way.
>>
>> >
>> > Anyway it was working with the uart in polling mode so it should work
>> also in interrupt mode without changing any RTEMS parameter right?
>>
>> I don't know enough about the implementation of the serial port driver to
>> answer this.
>>
>> --
>> Eric Norum
>> wenorum at lbl.gov
>>
>>
>
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