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Subject: Re: [PATCH 00/20] powerpc: Convert power off logic to pm_power_off
From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Date: Wed, 1 Oct 2014 17:39:13 -0500
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On Wed, 2014-10-01 at 15:27 +0200, Alexander Graf wrote:
> The generic Linux framework to power off the machine is a function pointer
> called pm_power_off. The trick about this pointer is that device drivers can
> potentially implement it rather than board files.
> 
> Today on PowerPC we set pm_power_off to invoke our generic full machine power
> off logic which then calls ppc_md.power_off to invoke machine specific power
> off.
> 
> However, when we want to add a power off GPIO via the "gpio-poweroff" driver,
> this card house falls apart. That driver only registers itself if pm_power_off
> is NULL to ensure it doesn't override board specific logic. However, since we
> always set pm_power_off to the generic power off logic (which will just not
> power off the machine if no ppc_md.power_off call is implemented), we can't
> implement power off via the generic GPIO power off driver.
> 
> To fix this up, let's get rid of the ppc_md.power_off logic and just always use
> pm_power_off as was intended. Then individual drivers such as the GPIO power off
> driver can implement power off logic via that function pointer.
> 
> With this patch set applied and a few patches on top of QEMU that implement a
> power off GPIO on the virt e500 machine, I can successfully turn off my virtual
> machine after halt.

Are there any plans to handle restart similarly?

-Scott