Re: [Xenomai-help] rtdm_event_timedwait returns -EINTR

[Philippe Gerum <rpm@xenomai.org>]

On Mon, 2009-05-04 at 16:22 +0200, Philippe Gerum wrote:
> On Mon, 2009-05-04 at 16:20 +0200, Petr Cervenka wrote:
> > >Assuming you are using the native API (the POSIX interface would have to
> > >be adapted the same way), does the following patch help?
> > >
> > 
> > The patch doesn't make any difference. It could be because I use mostly rtdm skin in the driver, not native. And the native skin example already resets syscall (but with wrong timeout).
> > 
> > Meanwhile I have found out the type of the signal, which interrupts my syscalls. It's SIGWINCH (or perhaps SIGHARDEN). What is exactly this signal used for, should it be interrupting syscalls?
> 
> This is a signal internally used by skins to force a thread in primary
> mode; it should not do interrupt syscalls, provided we set the sigaction
> flags properly.
> 

Read: it must interrupt Xenomai syscalls internally but the latter
should always be silently restarted, by properly setting the SA_RESTART
bit in the sigaction flags for that signal.

Not allowing Linux to interrupt blocking Xenomai syscalls to process
pending signals would basically kill GDB support, and beyond this create
a very fragile situation wrt signal handling and Xenomai, which is the
last thing we would want to do.

> > 
> > Petr
> > 
-- 
Philippe.