How? PM suspend resume code in misc driver?

How? PM suspend resume code in misc driver?

[TJ]

I've been trying to figure out how a misc char driver (in this case
acerhk) can link into PM suspend and resume events. I found the patches
from 2008-02 that introduced a 'heavy-handed' mechanism to misc that
were quickly removed by another set of patches in 2008-04.

In the removal patches there is mention of a 'better way of doing it'
but I've not been able to locate any documentation to that end.

The precise requirement is to fix a problem for a user of a laptop that
'forgets' the state of the RF frequency kill switch during suspend. When
the PC resumes the radio is off and the hardware button has to be
manually activated.

The acerhk module is the only way to enable use of the kill-switch on
this PC.

My thought was that if acerhk can link into the PM events it can use the
resume event to re-enable the radio if it was enabled on suspend.

In this particular case it seems from the user's description that the
hardware switch is a momentary push-to-make type rather than a latching
switch that is more common.

Re: How? PM suspend resume code in misc driver?

[Henrique de Moraes Holschuh]

On Fri, 20 Mar 2009, TJ wrote:
> The precise requirement is to fix a problem for a user of a laptop that
> 'forgets' the state of the RF frequency kill switch during suspend. When
> the PC resumes the radio is off and the hardware button has to be
> manually activated.

Port that driver to rfkill, instead.  It does PM and will do the right
thing across suspend/resume.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh