Re: [Xenomai-help] serial com errors

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Yigal Goldberger wrote:
> Hi Again,
> 
> I hope it's not too long and tiring ...
> But the relevant code (I think...) is the initialization stage , and the select and read loop that blocks and reads .
> 
> 
> The problem is as follows :
> I have 2 threads listening on two different serial coms . running the same code below . Using select to block and wait for bytes to be available on the port , and then reading them with the read function .
> These 2 threads are Xenomai threads with priority higher then the thread that is responsible of working on the data .
> I see that when reaceiving with BAUDRATES lower than 115200 (38400) no problem occures , and when receving on both port with BAUDRATE 115200 , I get errors in the received bytes ( which is identified by a wrong checksum ,and sometimes with a "No more room in flip buffer" printout on the console as well as errno 11 (EAGAIN) ) . When I added a 10 mili second sleep to the executing thread (the thread that uses the data )the problem seems to disappear .
> 
> 
> Below is the 2 code parts that Initialize the file descriptor of the reading thread , and the reading select - read loop :
> 
> 
> The code  creating the file descriptor :
> 
> 
> fd = open (devname, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK );

By the way, depending on the value of "devname" here, the file
descriptor may or may not be related to a real-time driver. And I
suspect in your case, it is not, because I do not think things like
cfsetispeed/cfsetospeed work with the real-time 16550 driver (the only
serial driver which is part of xenomai distribution).

-- 
					    Gilles.