What's the situation with OpenCL support in Calc now?

The option to enable OpenCL:
“Tools” / “Options” / “LibreOffice” / “OpenCL” / “Allow use of OpenCL”
seems to default to off now.
Not only that it seems to take two or three attempts to actually turn it on.
Why is that?
Is it safe to turn it on?

On the latest versions LibreOffice does a test to verify that OpenCL is usable.

Take a look to this Michael’s blog post, search for hardware accelaration.

https://people.gnome.org/~michael/blog/2017-02-01-under-the-hood-5-3.html

Once I turn it on it stays on. But why is it so difficult to get it to turn on? Why do I even need to turn it on, why isn’t it just testing and deciding for itself?

You can turn it on at your own risk about right results for your calculations, it is turn off because doesn’t pass the test. If Software interpretes was on I have not found a relevant speed difference with OpenCL.

But I’ve never received a single message about a test being failed. Surely some message would be shown?
What OpenCL hardware and drivers definitely do work properly?
I’ve never seen the option default to enabled, not once.

You can look for OpenCL issues on bugzilla and also add your onw report.

http://www.libreoffice.org/get-help/feedback/ - Create a bug report.