Feature request, but must be universallly accepted by ALL blanker authors

Aaron Plattner aplattner at nvidia.com
Fri Oct 2 23:55:53 UTC 2020


On 10/2/20 1:17 PM, Dan Arena wrote:
> Gene,
> 
> Following up more about xfce4, you should be able to go into their
> Settings Manager and you can turn off the Screensaver and uncheck
> Power Management under the Advanced tab. You will still want to add
> the lines I mentioned before into /etc/X11/xorg.conf to prevent the
> screen from going blank though.
> 
> I also think it would be a useful feature for LinuxCNC to include an
> option where it itself can prevent screensavers. This would not be too
> hard for them to do, see https://stackoverflow.com/a/31504731/1941627
> 
> A friend also just brought up a good point... do these machines not
> have a physical emergency stop button? It seems like with them being
> as dangerous as you say they are, they should. I know the couple mills
> I have seen do.

I agree with this. There are so many things that could go wrong between 
the keyboard and software commanding the machine to stop (swapping 
prevents something from getting scheduled, interrupt storm from a rogue 
device delays processing, etc.). If this is really a safety critical 
feature then everything in the system along this path needs to have 
realtime guarantees, redundancy, and follow something like MISRA coding 
standards.

It would be *way* easier and cheaper to put a big red stop button on the 
machine itself, and bypass this problem of screen locking programs entirely.

I would not recommend relying on the computer for this.

-- Aaron

> I would also take this issue up with the LinuxCNC community. Is it
> supposed to work like that? Does a new install from the LinuxCNC
> "Install DVD" behave the same?
> 
> Thanks,
> Dan


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