[Xenomai-help] rtser not showing up

[Xenomai-help] rtser not showing up

[Brandt Erickson]

Hi,
I'm trying to get realtime communication over the serial port to work
using the example found here

	http://www.captain.at/xenomai-serial-port-example.php

I compiled a 2.6.20-6 kernel with xenomai-2.3.1 and configure the
realtime serial driver to be a loadable module.  I disabled the default
linux serial driver using 'setserial'.  However, when I run

	modprobe xeno_16550A ioaddr=0x3f8 irq=4
or
	insmod ./xeno16550A.ko ioaddr=0x3f8 irq=4

no rtser<N> nodes turn up in /dev.  No errors are generated when I
insert the module and an lsmod reveals it is in.  Have I missed
something?  Thanks.
-Brandt

Re: [Xenomai-help] rtser not showing up

[Gilles Chanteperdrix]

Brandt Erickson wrote:
 > Hi,
 > I'm trying to get realtime communication over the serial port to work
 > using the example found here
 > 
 > 	http://www.captain.at/xenomai-serial-port-example.php
 > 
 > I compiled a 2.6.20-6 kernel with xenomai-2.3.1 and configure the
 > realtime serial driver to be a loadable module.  I disabled the default
 > linux serial driver using 'setserial'.  However, when I run
 > 
 > 	modprobe xeno_16550A ioaddr=0x3f8 irq=4
 > or
 > 	insmod ./xeno16550A.ko ioaddr=0x3f8 irq=4
 > 
 > no rtser<N> nodes turn up in /dev.  No errors are generated when I
 > insert the module and an lsmod reveals it is in.  Have I missed
 > something?  Thanks.
 > -Brandt

No node will turn up in /dev, you will find the list of available RTDM
devices in /proc/xenomai/rtdm/named_devices.

-- 


					    Gilles Chanteperdrix.

Re: [Xenomai-help] rtser not showing up

[Brandt Erickson]

> No node will turn up in /dev, you will find the list of available RTDM
> devices in /proc/xenomai/rtdm/named_devices.

Okay,
there is a /proc/xenomai/rtdm/rtser0.  The example opens the file
"rtser0", does this default to the full path name when I use
rt_dev_open?

Right now, it appears I can open the file (rt_dev_open returns 0) and
configure the serial port (using rt_dev_ioctl), however, every call to
rt_dev_write returns -1.  I'm using the configuration from the example
code which basically has everything set to defaults.  Is there an
equivalent of errno I can get to find out what's going wrong?  Thanks.
-Brandt

Re: [Xenomai-help] rtser not showing up

[Brandt Erickson]

> Right now, it appears I can open the file (rt_dev_open returns 0) and
> configure the serial port (using rt_dev_ioctl), however, every call to
> rt_dev_write returns -1.  I'm using the configuration from the example
> code which basically has everything set to defaults.  Is there an
> equivalent of errno I can get to find out what's going wrong?  Thanks.
> -Brandt

Slight modification here, it does write correctly if I call rt_dev_write
from a task spawned by main, but not if I call it from main itself.  So
I guess this is less about rtser per se and more about the rtdm API.

Re: [Xenomai-help] rtser not showing up

[Gilles Chanteperdrix]

Brandt Erickson wrote:
 > 
 > > No node will turn up in /dev, you will find the list of available RTDM
 > > devices in /proc/xenomai/rtdm/named_devices.
 > 
 > Okay,
 > there is a /proc/xenomai/rtdm/rtser0.  The example opens the file
 > "rtser0", does this default to the full path name when I use
 > rt_dev_open?
 > 
 > Right now, it appears I can open the file (rt_dev_open returns 0) and
 > configure the serial port (using rt_dev_ioctl), however, every call to
 > rt_dev_write returns -1.  I'm using the configuration from the example
 > code which basically has everything set to defaults.  Is there an
 > equivalent of errno I can get to find out what's going wrong?  Thanks.
 > -Brandt

The errors of the serial driver are documented here:

http://www.xenomai.org/documentation/trunk/html/api/group__rtserial.html

-1 is -EPERM... which is not documented. -EPERM probably means that you
are trying to use a real-time call from a non real-time thread. See
rt_task_shadow or rt_task_create.

-- 


					    Gilles Chanteperdrix.

Re: [Xenomai-help] rtser not showing up

[Jan Kiszka]

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Gilles Chanteperdrix wrote:
> Brandt Erickson wrote:
>  > 
>  > > No node will turn up in /dev, you will find the list of available RTDM
>  > > devices in /proc/xenomai/rtdm/named_devices.
>  > 
>  > Okay,
>  > there is a /proc/xenomai/rtdm/rtser0.  The example opens the file
>  > "rtser0", does this default to the full path name when I use
>  > rt_dev_open?
>  > 
>  > Right now, it appears I can open the file (rt_dev_open returns 0) and
>  > configure the serial port (using rt_dev_ioctl), however, every call to
>  > rt_dev_write returns -1.  I'm using the configuration from the example
>  > code which basically has everything set to defaults.  Is there an
>  > equivalent of errno I can get to find out what's going wrong?  Thanks.
>  > -Brandt
> 
> The errors of the serial driver are documented here:
> 
> http://www.xenomai.org/documentation/trunk/html/api/group__rtserial.html
> 
> -1 is -EPERM... which is not documented. -EPERM probably means that you
> are trying to use a real-time call from a non real-time thread. See
> rt_task_shadow or rt_task_create.
> 

That's the point. The serial driver's write operation requires real-time
context and return -EPERM otherwise. Documentation should be enhanced...

Jan


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