Re: [Xenomai-help] rtdm_printk

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

Gilles Chanteperdrix wrote:
> Jeff Weber wrote:
>> When writing a RTDM kernel module driver, when must rtdm_printk() be used
>> instead of printk() ?
> 
> If RTDM was, one day, ported over something else than a Linux
> kernel-space based solution (for instance, over a port of Xenomai
> without Linux, or in Linux user-space), then you would not have to
> change your driver codeto have it compile over that new port.
> 
> Until then, printk and rtdm_printk are identical.
> 
> Note that the first paragraph is something very hypothetical, because in
> an RTDM driver, you generally have some other Linux kernel-space
> specific code, such as for instance the registration as a PCI driver,
> though the necessary parts of the Linux API could be implemented for
> that hypothetical port. But in that case, so could printk.
> 
> So...

I guess the real reason for rtdm_printk is that at some point in the
past (probably before the Adeos era), printk was not safe to be called
from the real-time domain. In that case, rtdm_printk would be safe to be
called from the real-time domain. So, the answer is that you should use
rtdm_printk if you are calling from a Xenomai domain interrupt handler,
or from the context of a thread running in primary mode.

-- 
					    Gilles.