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

[Jeshwanth Kumar N K <jeshkumar555@xxxxxxxxx>]

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@xxxxxxxxx> 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@xxxxxxxxx> 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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