linux-kernel - Re: [STLinux Kernel] [PATCH 0/7] reset: Consumers to explicitly request 'exclusive' or 'shared' lines

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Date:	Tue, 7 Jun 2016 10:24:56 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Peter Griffin <peter.griffin@...aro.org>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	balbi@...nel.org, kernel@...inux.com,
	srinivas.kandagatla@...il.com, linux-usb@...r.kernel.org,
	kishon@...com, p.zabel@...gutronix.de, gregkh@...uxfoundation.org
Subject: Re: [STLinux Kernel] [PATCH 0/7] reset: Consumers to explicitly
 request 'exclusive' or 'shared' lines

On Tue, 07 Jun 2016, Lee Jones wrote:

> On Tue, 07 Jun 2016, Peter Griffin wrote:
> 
> > Hi,
> > 
> > On Mon, 06 Jun 2016, Lee Jones wrote:
> > 
> > > Phasing out generic reset line requests enables us to make some better
> > > decisions on when and how to (de)assert said lines.  If an 'exclusive'
> > > line is requested, we know a device *requires* a reset and that it's
> > > preferable to act upon a request right away.  However, if a 'shared'
> > > reset line is requested, we can reasonably assume sure that placing a
> > > device into reset isn't a hard requirement, but probably a measure to
> > > save power and is thus able to cope with not being asserted if another
> > > device is still in use.
> > > 
> > > In order allow gentle adoption and not to forcing all consumers to
> > > move to the API immediately, causing administration headache between
> > > subsystems, this patch adds some temporary stand-in shim-calls.  This
> > > will ease the burden at merge time and allow subsystems to migrate over
> > > to the new API in a more realistic time-frame.
> > 
> > Is the intention that this series will be taken into the next -rc?
> > 
> > As the introduction of shared resets in reset subsystem has caused regressions
> > on STi platforms.
> 
> Yes, which is why it has a Fixes: tag.

Ah wait.  I thought this was the shared-memory patch.

More haste, less speed and all that.

I guess it should really go into the -rcs, yes.  Since Hans' patch
actually breaks a lot of devices.  I'm pretty surprised a patch
capable of this much damage was actually accepted to be honest.  A
better approach would have been to issue a warning, but keep the
semantics the same for at least a couple of releases.  However, I
guess the damage has been done now, so let's do what we can do fix
it.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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