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From: Johannes Berg <johannes@sipsolutions.net>
To: "Yan, Zheng" <zheng.z.yan@intel.com>
Cc: wey-yi.w.guy@intel.com, ilw@linux.intel.com,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH RFC] iwlwifi: add basic runtime PM support
Date: Fri, 06 Jan 2012 10:47:49 +0100	[thread overview]
Message-ID: <1325843269.3330.4.camel@jlt3.sipsolutions.net> (raw)
In-Reply-To: <4F065F59.2070107@intel.com>

[add linux-wireless]

On Fri, 2012-01-06 at 10:41 +0800, Yan, Zheng wrote:
> This simple patch adds open/close based runtime PM support to the iwlwifi driver.
> Namely, make the driver suspend the device after shutting down the interface and
> resume the device when activating the interface. In my test, suspending the device
> can save about 0.4 watt power. The shortcoming is that the device no longer generate
> rfkill changes interrupt.

NACK due to that last sentence. There's no way we can live with that in
the general case -- and your patch isn't even configurable afaict. And
I'm sure polling the rfkill flag would use just as much energy.

There might be some value in this in a system that doesn't have a hard
rfkill line, but that means this needs to be configurable since the
device can't know whether there's a button or not [1].

johannes

[1] actually in theory it might be possible to determine whether or not
the pin is floating or not? I doubt even that is possible with the HW we
have though


       reply	other threads:[~2012-01-06  9:47 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4F065F59.2070107@intel.com>
2012-01-06  9:47 ` Johannes Berg [this message]
2012-01-09  1:01   ` [PATCH RFC] iwlwifi: add basic runtime PM support Yan, Zheng
2012-01-09  0:34     ` Guy, Wey-Yi
2012-01-09  1:55       ` Yan, Zheng
2012-01-09  1:05         ` Guy, Wey-Yi
2012-01-09  9:04           ` Yan, Zheng
2012-01-09  9:11           ` Johannes Berg
2012-01-09 14:39             ` Guy, Wey-Yi
2012-01-09  9:10     ` Johannes Berg

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