From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: Re: [v4,1/9] ACPI / PM: Let acpi_dev_pm_detach() return an error code
Date: Mon, 15 Sep 2014 09:53:59 -0700
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To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Ulf Hansson <ulf.hansson@linaro.org>, Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, Kevin Hilman <khilman@linaro.org>, Russell King <linux@arm.linux.org.uk>, Philipp Zabel <philipp.zabel@gmail.com>, Geert Uytterhoeven <geert+renesas@glider.be>, Wolfram Sang <wsa@the-dreams.de>, Stephen Boyd <sboyd@codeaurora.org>, Linus Walleij <linus.walleij@linaro.org>, Daniel Lezcano <daniel.lezcano@linaro.org>, Magnus Damm <magnus.damm@gmail.com>, Tomasz Figa <tomasz.figa@gmail.com>, Chris Ball <chris@printf.net>, linux-acpi@vger.kernel.org, Simon Horman <horms@verge.net.au>, Alan Stern <stern@rowland.harvard.edu>, Mark Brown <broonie@kernel.org>, Ben Dooks <ben-linux@fluff.org>, Kukjin Kim <kgene.kim@samsung.com>, linux-arm-kernel@lists.infradead.org
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On Sun, Sep 14, 2014 at 06:38:58PM +0200, Rafael J. Wysocki wrote:
> On Friday, September 12, 2014 02:05:53 PM Dmitry Torokhov wrote:
> > Hi Ulf,
> > 
> > On Tue, Sep 09, 2014 at 01:36:02PM +0200, Ulf Hansson wrote:
> > > To give callers the option of acting on a errors while removing the
> > > pm_domain ops for the device in the ACPI PM domain, let
> > > acpi_dev_pm_detach() return an int to provide the error code.
> > 
> > So how would callers handle the errors? As far as I can see
> > acpi_dev_pm_detach() is called from ->remove() and ->shutdown() methods, where
> > there is no meaningful strategy to handle errors as you are past the point of
> > no return and you keep on tearing down the device.
> 
> This is specifically for what patch [3/9] is doing AFAICS.  
> 
> The existing callers don't need to worry about this.

OK, so I have the very same comment about patch 3 then: we have
dev_pm_domain_detach() returning error. How would the callers handle errors?

WRT this patch: I'd rater we did not just return generic "error code" just
because we do not know who manages PD for the device. Can we add API to check
if we are using ACPI to manage power domains? Then patch #3 could check if it
needs to use ACPI or generic power domain API.

Thanks.

-- 
Dmitry