radio off guarantee?

[Dan Williams]

On Tue, 2007-09-18 at 15:33 -0400, Richard A. Smith wrote:
> John Watlington wrote:
> 
> > While it makes sense to turn off the wireless networking interface on  
> > developer
> 
> So there's a slight problem with powering off the wireless interface 
> from an electrical standpoint.  You can't.
> At least not if you want a working system.
> 
> WLAN_EN controls WLAN_3.3V. +3.3V is derived from WLAN_3.3V.  So if you
> drop WLAN_3.3V you lose +3.3V and you also lose:
> 
> VDDIO on the LX700
> Pullups on the PCI bus.
> Pullups on the jtag lines
> Supply voltages for COREPLL, GLPLL, and DOTPLL on the LX700
> Power supply to the LX700 Therm alarm circuits
> Power supply to the system clock chip.
> 
> And lots of other stuff...you get the idea.  System no workie.
> 
> That leaves 3 alternatives:
> 
> 1 Don't load the wlan firmware.
> 2 Load the firmware and tell wlan xmit to shutdown
> 3 Hold the WLAN module in reset.
> 
> #3 Can be done via the EC but there's currently not a command to _hold_
> it in reset.  There is a reset WLAN command which will strobe the reset
> line for 1ms.  I can add enable/disable reset commands if 1 and 2 are
> not viable.

1 and 2 are certainly viable and should be the preferred methods I
think.  Note that right now trying to rmmod usb8xxx panics the kernel
for some reason.

Dan