Isn't Wifi supposed to be off by default?

Werner Almesberger werner at
Fri Jan 16 08:15:43 CET 2009

c_c wrote:
>   Well, just a basic doubt here. What about all of us that run their
> distributions off the mmc card? In such cases, removing ar6000.ko wont
> really help much since the clock would keep running.

It doesn't matter if you're running from MMC, because it's on a
different MMC bus :-) The GTA02 has two MMC busses: an MMC/SD/SDIO
bus off the controller in the S3C2442 (S3C MCI driver), which is
used exclusively for WLAN. And an SD/MMC bus connected via the
Glamo (Glamo MCI driver), which is used for microSD cards.

>   Is it at all possible to cut power to the WLAN module while the s3cmci.ko
> is inserted or is that a hardware implementation we need to live with?

There are several layers here:

- rmmod s3cmci.ko removes the module with the S3C MCI driver _and_
  powers down SDIO controller and WLAN function

- unbind s3c2440-sdi leaves the s3cmci.ko module in place but
  still powers down SDIO controller and WLAN function

- rmmod ar6000.ko removes the ar6000.ko module and powers down the
  WLAN function (but not the SDIO controller)

- rfkill leaves the ar6000.ko module in place but still powers
  down the WLAN function

- wmiconfig does not remove any modules nor does it power down
  entire controllers or chips, but it changes the operating state
  of the WLAN function

"WLAN module" here refers to the hardware component, not the
kernel module.

"WLAN function" here is the part of the WLAN module that
implements, well, WLAN. In front of this is the SDIO bus
interface of the WLAN module. The WLAN function can be powered
down internally in the WLAN module. We never power down the SDIO
bus interface in the WLAN module, but we can power down the
interface on the host side and stop the SDIO clock.

Hope this spreads the confusion more evenly ;-)

- Werner

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