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From: Johannes Stezenbach <js@sig21.net>
To: Kalle Valo <kvalo@adurom.com>
Cc: Ivo van Doorn <ivdoorn@gmail.com>,
	users@rt2x00.serialmonkey.com, linux-wireless@vger.kernel.org
Subject: Re: [RFC] rt2x00: Add autowakeup timer for receiving beacons while in powersave mode
Date: Wed, 2 Feb 2011 22:29:12 +0100	[thread overview]
Message-ID: <20110202212912.GA28687@sig21.net> (raw)
In-Reply-To: <874o8mbaec.fsf@purkki.adurom.net>

On Wed, Feb 02, 2011 at 07:42:51PM +0200, Kalle Valo wrote:
> So the firmware/hardware doesn't have support for tracking and waking
> up for beacons? I didn't even know that such hardware exists :) Waking
> up for beacons from host sounds very inefficient and unrealiable. All
> the devices I have seen either do this in firmware or hardware due to
> time constraints. Even at76c50x-usb, which is ancient, does all this
> in firmware.

IMHO this is a bit exaggerated.  Given that the beacon interval
is typically ~100 msecs, and typical worst cast irq latencies
on Linux 2.6 are a few 100 usecs, we can sleep e.g. 90msecs
and wake up in time to catch the beacon with high probability, thus
saving 90% on PHY power.  Not perfect, but good enough, isn't it?


Johannes

  parent reply	other threads:[~2011-02-02 21:29 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-31 15:00 [RFC] rt2x00: Add autowakeup timer for receiving beacons while in powersave mode Ivo van Doorn
2011-01-31 15:22 ` Johannes Berg
2011-01-31 15:38   ` Ivo Van Doorn
2011-01-31 15:54     ` [rt2x00-users] " Johannes Stezenbach
2011-01-31 18:17 ` Johannes Stezenbach
2011-01-31 19:00   ` Ivo Van Doorn
2011-01-31 21:05     ` Johannes Stezenbach
2011-02-02 17:42 ` Kalle Valo
2011-02-02 19:09   ` Ivo Van Doorn
2011-02-10  5:24     ` RA-Jay Hung
2011-02-14 10:14       ` Ivo Van Doorn
2011-02-14 10:25         ` Johannes Berg
2011-02-02 21:29   ` Johannes Stezenbach [this message]
2011-02-07 23:33     ` [rt2x00-users] " Aleksandar Milivojevic
2011-02-08  8:48       ` Kalle Valo
2011-02-08 19:11         ` Aleksandar Milivojevic
2011-02-09 12:17           ` Kalle Valo
2011-02-09 14:31           ` Johannes Stezenbach
2011-02-08  8:27     ` Kalle Valo
2011-02-08 20:09       ` Johannes Stezenbach

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