Re: [PATCH] thinkpad_acpi: save kbdlight state on suspend and restore it on resume

[Darren Hart <dvhart@infradead.org>]

On Fri, May 20, 2016 at 05:03:52AM +0200, Marco Trevisan (Treviño) wrote:
> 2016-05-19 9:52 GMT+02:00 Pali Rohár <pali.rohar@gmail.com>:
> > For me whole patch looks like a big hack because LED_CORE_SUSPENDRESUME
> > does not work correctly... I would rather see fixed support for flag
> > LED_CORE_SUSPENDRESUME, not adding another suspend/resume hook if
> > possible. Any idea?
> 
> As I wrote you in private mail I think the only way we have is to keep
> the led_cdev->brightness in sync with actual state. And to do this, we
> can listen the ACPI event, keeping this like a private event that we
> just consume to update led brightness value, without delivering it to
> userspace.
> 
> However, the custom code needed for getting this done, is probably way
> more than the one I added here.
> Maybe it could be useful to others to read the brightness level before
> suspending, and in this case we could add a new flag to the led
> subsystem, but not sure it's really worth.
> 

At the risk of contributing to "the platform platform", I agree with a local fix
here in the near term. If this becomes a pattern, we can look to move this into
the LED subsystem. As it is, this is working as designed, overriding when
necessary.

-- 
Darren Hart
Intel Open Source Technology Center