Re: Network drivers that don't suspend on interface down

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On Wed, 20 Dec 2006, Dan Williams wrote:

If we define interface down as meaning that the device is powered down
and the radio switched off, then (b) and (c) would presumably just need
to ensure that the interface is downed. (a) is a slightly more special
case - if the switch disables the radio, I guess we then want the driver
to down the interface as well.

Correct.

In the (a) case, drivers should presumably refuse to bring the interface
up if the radio is disabled?

Right; the driver simply can't do anything about it, because the switch
is hardwired to the card and either the card's firmware takes care of
it, or the chipset takes care of it.  The driver has no say whatsoever
in the state of the card's radio for this case.  I tend to think this
case is on it's way out in the same way that fullmac cards are falling
out of favor (ie, do everything in software and save $$$), but they are
around and we need to support them.

In this case, down really does mean down too.  The driver cannot honor
requests to set SSID, frequency, etc, because it's simply not possible
at that time.

What do you mean with this exactly?
Should the user not be able to set these values, or should the driver not be able to activate them?

I think it is correct when the driver does not activate them, but I think the user should be able to configure them, have them stored inside cfg80211/the driver, and have them activated/used when uping the interface, or when the rfkill switch has been deactivated. Otherwise it will get impossible to boot with rfkill disabled, toggle the switch later on and have everything working.

And another side to this:
if a disabled rfkill switch downs the interface (opposed to just disabling it but staying "ifconfig up") - what happens to the ip config of this interface? What reconfigures the needed routes when a re-enabled rfkill switch reactivates the interface? Will manual route add and ifconfig statements be impossible and we'll get forced to use some crappy distri-scripts and daemons for it?

And third point just coming to my mind:
how is changing the mac address of the card supposed to work? Chaning it through ifconfig only works when the interface is downed, so the newly wanted mac address has to be saved somewhere before the interface is reenabled and reinitialized on the next "ifconfig up". (And I think it is an absolute requirement that NO packet with the old/default mac address may be sent into the air whatsoever)

c'ya
sven

--

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