WLAN vs. suspend/resume (stable-tracking)

[Werner Almesberger]

Let's put this into a new thread.

With the recent fixes, s3cmci survives suspend/resume or module
removal and re-insertion.

However, the AR6k module is not detected on resume or insertion.
This happens whether I load the ar6k WLAN stack (ar6000.ko) or
not, so it's a problem between the AR6k module and the SDIO stack.

A work-around to bring WLAN back to life after resume is to build
s3cmci as a module and to do the following:

# rmmod s3cmci.ko
# echo 0 >/sys/bus/platform/drivers/gta02-pm-wlan/gta02-pm-wlan.0/power_on
# echo 1 >/sys/bus/platform/drivers/gta02-pm-wlan/gta02-pm-wlan.0/power_on
# insmod s3cmci.ko

The SDIO stack isn't sending anything nasty to the module on suspend
or removal. On resume/insertion without a prior reset, the command
sequence is as follows:

CMD0 (reset) -> OK
CMD8 (check voltage MMC-style) -> timeout
CMD5 (check voltage SDIO-style) -> timeout

CMD5 is where we depart from the normal initialization sequence.
The normal response would be an acknowledgement.

So it seems that CMD0 doesn't return the card to Idle. Time to
look at what's going on on the wire ...

- Werner