hid-rmi: configuration automatically changed after suspend/resume

[Gabriele Mazzotta <gabriele.mzt@gmail.com>]

Hi,

I recently noticed that there's a minor issue with hid-rmi.c. After a
suspend/resume cycle the f11 control register is set to the default
configuration, thus undoing the changes performed on init.

I made some changes to the driver to prevent this from happening: the
configuration is saved on suspend and restored upon resume. This seemed
the simplest thing to do, but I encountered a small problem.

I'm saving and writing the whole register since the kernel can't know
what userspace tools might have done. According to a comment in the
sources, some firmwares split the control register, so blindly copying
and writing 20 sequential bytes as I'm doing could be a problem.

Is there a way to recognize those firmwares? Or even better, is there a
way to prevent the firmware from restoring the default configuration?

PS: I didn't check if the same happens with other registers, but I
suspenct it does.

Thanks,
Gabriele