[PATCH 48/74] GIC: Added dummy handlers for Power Management Suspend Resume

On 9/8/2010 8:42 PM, Russell King - ARM Linux wrote:

On Mon, Sep 06, 2010 at 05:25:31PM +0530, deepaksi wrote:
  

quoted

On 9/3/2010 1:04 PM, Russell King - ARM Linux wrote:
    

quoted

So how are wakeup sources configured if this callback does nothing?
.
      

In most of the architectures that I could refer across(including SPEAr
family -SPEAr13xx),
have a separate power management unit(PMU) which is required to be
configured to define the wake
up sources. The PMU takes care of waking up the system from sleep, as
and when the wake up
interrupts are triggered. This routing is independent of GIC, and hence
the handling was not added.

Contrary to that, in some of our hardware architecture using VIC
(including SPEAr 3xx/6xx), there
was no explicit PMU, and the wake up trigger was exclusively done
through VIC, and hence the VIC
call backs had the necessary implementation.
    

What I read into this is that you're using enable_irq_wake() in your
drivers _and_ another mechanism to configure what wakes up the system
via the PMU - maybe with drivers explicitly calling out to the PMU
to achieve this?
  

This is even true for the drivers already in the kernel for example
stmmac driver ( using synopsis GMAC core): drivers/net/stmmac/
if we don not check for the return type, then probably it makes sense to
remove the dunny handlers, else another alternative could be to modify
the enable_irq_wake() call, to return the proper values.

Changing the driver specific to SPEAr is fine, but SPEAr platform does
uses the existing drivers in the kernel.

This sounds a little haphazard, especially from the drivers point of
view.  Surely there's a more sensible solution to this rather than
adding do-nothing irq_wake support?
.

  

How do you recommend to go about this ?