Re: [PATCH] b44: power down PHY when interface down
- From: Lennert Buytenhek <buytenh@xxxxxxxxxxxxxx>
- Date: Sun, 1 Jul 2007 00:03:01 +0200
On Sat, Jun 30, 2007 at 11:53:25PM +0200, Michael Buesch wrote:
When the interface is down (or driver removed), the BroadCom 44xx card remains
powered on, and both its MAC and PHY is using up power.
This patch makes the driver issue a MAC_CTRL_PHY_PDOWN when the interface
is halted, and does a partial chip reset turns off the activity LEDs too.
Applies to 2.6.22-rc6, or current git head.
Tested on a Broadcom BCM4401-B0 card, it saves ~0.5W (measured using powertop).
Hm, I was going to measure the real power advantage with a
PCI-extender card. But my B44B0 card doesn't seem to work in
that extender card. It works perfectly fine sticked directly into
the motherboard, though, and other cards like a BCM4318 work in
the extender, too.
Not sure what this is.
The extender has an application note about nonworking cards in the
extender and a too big resistor on the board IDSEL pin being the
cause of this.
Does the card show up in lspci at all? IDSEL drive strength
issues should only affect config space accesses.
Does the extender board have a PCI-PCI bridge on it? (If not,
there's not really any reason to resistively couple the IDSEL
line to the host, since the host should take care of that.)
Maybe I can try with another machine tomorrow.
That would only make a difference if there is no PCI-PCI bridge on
the extender board.
If the extender resistively couples the host's IDSEL line, you might
see different results on a different host bridge, since different
host bridges can use different numbers of IDSEL stepping cycles.
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