Subject: Re: [ipw3945-devel] [BUG] iwlwifi 3945 works only with
	disable_hw_scan=1
From: Zhu Yi <yi.zhu@intel.com>
To: Dan Williams <dcbw@redhat.com>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>,
	linux-wireless@vger.kernel.org, ipw3945-devel@lists.sourceforge.net
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Date: Fri, 13 Jun 2008 10:00:39 +0800
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On Thu, 2008-06-12 at 11:02 -0400, Dan Williams wrote:
> > I guess that the right solution is to listen to the wireless button
> (via 
> > input layer), and turn card on manually.
> > 
> > If I remember correctly there is something like that in kernel, I
> try to 
> > enable this.
> > 
> > Otherwise this can be implemented in userspace.
> 
> The right solution is for NM to not take the device down (essentially
> doing SIOCSIFFLAGS with !IFF_UP), but to set the TX power off.
> However,
> that's not possible right now, because HAL doesn't provide enough
> information about the killswitches to distinguish between a software
> rfkill (which means we can turn the power back on) and a hardware
> rfkill
> (which means the user has to flip something).  On ipw2100, 2200, and
> 2915, setting the TX power off looks exactly like a hardware kill to
> HAL, so if you chose unchecked "Enable Wireless" in the nm applet,
> you'd never be able to turn wireless back on, because HAL and NM think
> there's a hardware kill active.

I think who takes the interface down is responsible to bring it up. Even
if the driver receives a rf_kill switch disabled interrupt, it should
keep the current IFF_UP status. It should never bring it up or down
itself. (Think about the carrier on/off in ethernet).

I wonder why NM need to ifdown or "txpower off" when rf_kill switch
(both for SW and HW) is enabled. The driver already handles it. Could it
save more power?

Thanks,
-yi