Date: Tue, 19 May 2015 13:49:15 -0400 (EDT)
From: Alan Stern <stern@rowland.harvard.edu>
To: Tomeu Vizoso <tomeu.vizoso@collabora.com>
cc: linux-pm@vger.kernel.org,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Kevin Hilman <khilman@linaro.org>,
        Russell King <rmk+kernel@arm.linux.org.uk>,
        Krzysztof Kozlowski <k.kozlowski@samsung.com>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] PM / Runtime: Add pm_runtime_enable_recursive
In-Reply-To: <1432044679-10256-3-git-send-email-tomeu.vizoso@collabora.com>
Message-ID: <Pine.LNX.4.44L0.1505191345480.1453-100000@iolanthe.rowland.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 956
Lines: 24

On Tue, 19 May 2015, Tomeu Vizoso wrote:

> This function makes less cumbersome to enable runtime PM in a device and
> its descendants.
> 
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>

I don't see the point of this.  In the scenario you have in mind, are
the device and all its descendants registered by the same
subsystem/driver?  If they are, can't the subsystem/driver code enable
runtime PM for each of them when they are registered, by adding a
single call in the right spot?

If they don't all belong to the same subsystem/driver, who is going to 
call your pm_runtime_enable_recursive routine?  No single caller will 
have the right to enable runtime PM for all these devices.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/