User space <==> kernel space for device wakeups.

Jeshwanth Kumar N K jeshkumar555 at gmail.com
Wed Oct 8 12:31:43 EDT 2014


Greg, then what will you suggest for my case? I mean any alternative ?

Thanks

On Wed, Oct 8, 2014 at 9:55 PM, Greg Kroah-Hartman <greg at kroah.com> wrote:

> On Wed, Oct 08, 2014 at 05:57:50PM +0200, Kristof Provost wrote:
> > On 2014-10-08 21:14:43 (+0530), Jeshwanth Kumar N K <
> jeshkumar555 at gmail.com> wrote:
> > > Wayback when I was working on some project to wake up userspace
> program for
> > > every rising edge in GPIO pin (hall sensor), I use to send signal to
> the
> > > PID from kernel, before that userspace has to register its PID with
> kernel
> > > module.
> > >
> > I've seen a certain vendor[1] do something similar. They saved the task
> > pointer for whichever process made the magical ioctl() call and used it
> > to send signals from the interrupt handler. It worked, right up to the
> > point where the process went away and then the kernel panicked.
>
> Exactly, don't do that :)
>
> Finding out the real problem that is attempting to be solved would be
> good...
>
> greg k-h
>



-- 
Regards
Jeshwanth Kumar N K
Bangalore, India
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