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Date: Mon, 14 Feb 2011 11:14:39 +0100
Message-ID: <AANLkTimRT-2B4G1jC4D+BZURmd_FRGSkLT5MKsEvcS3r@mail.gmail.com>
Subject: Re: [RFC] rt2x00: Add autowakeup timer for receiving beacons while in
 powersave mode
From: Ivo Van Doorn <ivdoorn@gmail.com>
To: RA-Jay Hung <Jay_Hung@ralinktech.com>,
	Johannes Berg <johannes@sipsolutions.net>
Cc: Kalle Valo <kvalo@adurom.com>,
	"users@rt2x00.serialmonkey.com" <users@rt2x00.serialmonkey.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	RA-Dennis Lee <Dennis_Lee@ralinktech.com>,
	RA-Eddy Tsai <Eddy_Tsai@ralinktech.com>
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Sender: linux-wireless-owner@vger.kernel.org

Hi,

>> Well the official Ralink driver also uses a timer to wakeup the hardware,
>> there are however registers which suggest support for autowake functionality.
>
>> Jay, Dennis, Eddy, can you explain a but how the autowake functionality is
>> implemented in the rt2800usb firmware?
>
> Current power saving and wake up procedure as below.
>
> PCI:
> 1. Driver sends power-save command to firmware to turn off RF/BBP and configure
> mac register (AUTO_WAKEUP_CFG) to set a hardware timer counter.
> 2. When hardware timer timeout, issue an interrupt and notify the driver.
> 3. Driver send wake up command to firmware to turn on RF/BBP and ready to process
> packets
>
> USB:
> 1. Driver sends power-save command to firmware to turn off RF/BBP and set
> a software timer to emulate the purpose of hardware timer.
> 2. When software timer timeout, driver sends wake up command to firmware to
> turn on RF/BBP and ready to process packets.

Thanks. So I'll add this routine to the rt2800usb driver then. :)

Johannes, if you don't want to add the complexity for checking the
"pending MC/BC frames" in
a received frame. Would you mind if I add some utility functions to
mac80211 then? That way the
logic is still shared for the drivers that need it, but it doesn't
impact the code paths in mac80211 itself...

> Note: for future projects, hw or firmware will take more psm mechanism to reduce
> some latency between firmware and host to save more power.

Cool :)

Thanks for the info.

Ivo