Re: Interrupt handling

[George Anzinger <george@mvista.com>]

Sanil K wrote:
> Hi all,
> 
> This may be a generic problem as far as a driver is concerned.
> 
> We need to handle an interrupt and inform the user space on the event and
> pass the data correspodning to the event.
> 
> The event can be informed through SIGNAL and the signal handler can be
> invoked in the user space. Then again for data, we need to have the
> "copy_to_user" mechanism .
> 
> Is there any other effective mechanism(s) to handle the interrupt. I mean
> we need to convey the event and or data to the user space(prefer -
> asynchronously).
> 
IF the amount of data is small, say a word or two or less, you can use the 
siginfo and a realtime signal.  This will get the data at the same time as the 
signal.  If you prefer to avoid the overhead of the signal, you can do 
sigwaitinfo() which avoids the floating point save/restore, but does require the 
task to wait (i.e. is not asynchronous).




-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml