From: Dan Malek <dan@mvista.com>
To: Tania Oka <tania@centurysys.co.jp>
Cc: linuxppc-embedded@lists.linuxppc.org
Subject: Re: power saving
Date: Mon, 07 May 2001 15:49:52 -0400 [thread overview]
Message-ID: <3AF6FC60.D5FE49D9@mvista.com> (raw)
In-Reply-To: 3AF638AC.659C8A1F@centurysys.co.jp
Tania Oka wrote:
>
> I would like to reduce power consumption on a custom MPC855T board.
This has been asked before, and you can read about it in mailing
list archives.
Basically, the MPC8xx processors have a dynamic power management
system that doesn't gain much from just doing something in the idle()
loop. The majority of the power is consumed by peripherals. If they
are not enabled, they automatically power down. All of the MPC8xx
drivers "do the right thing" on open and close to power up/down
peripherals.
If you have some very low power standby requirement, you need to add
lots of power management software to do things like power down/up
any external peripherals on your board, put DRAM in autorefresh
mode, shut down the clocks and put the processor into a deep sleep.
You could look at some of the PowerMac power management code for
design ideas.
-- Dan
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2001-05-07 19:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-07 5:54 power saving Tania Oka
2001-05-07 19:49 ` Dan Malek [this message]
2001-05-10 10:36 ` August Hoerandl
-- strict thread matches above, loose matches on Subject: below --
2003-08-25 16:35 mjstumpf
2003-08-25 16:52 ` Peter L. Ashford
2003-08-25 17:19 ` Mike Dresser
2003-09-02 17:25 ` Gordon Henderson
2007-11-20 0:41 Power Saving Stephen Clark
2007-11-20 0:54 ` Dave Jones
2007-11-20 1:05 ` Stephen Clark
2007-11-20 1:12 ` Dave Jones
2007-11-20 1:21 ` H. Peter Anvin
2007-11-27 22:31 ` Phillip Susi
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