Debian Hardware :: Testing Is Now Soft Blocking WiFi (ath5k)

Regularly updated debian testing on a netbook. I normally use wired ethernet, but I am pretty sure that I had wifi (wlan0) working normally a few days ago.

Today, I find that wlan0 has a soft block:

# rfkill list
0: phy0: Wireless LAN
Soft blocked: yes
Hard blocked: no

It seems that the kernel(?) is sending a udev event to set this:

# rfkill event
1408563052.478251: idx 0 type 1 op 0 soft 1 hard 0

# rfkill unblock wlan
works *unless* the wifi button on this laptop is used. Then I get an apparently permanent hard block.
rfkill cannot unblock, and repeated button actions do not clear.

Adding the no_hw_rfkill_switch to the ath7K driver ensures that the wifi button is disabled.

All this is new: I have been using wifi on this netbook for years without problems, so something has changed. I moved to systemd (sigh) maybe a month ago, so perhaps the root problem is a systemd udev bug.

The real problem is knowing where to look or bug report. Is it a recent change in the ath5k driver or kernel? IIRC I checked the driver and there were no recent commits. Likewise rfkill hasn't changed recently. More likely to be something around systemd udev, perhaps, given the mayhem systemd has caused on another machine here. Or perhaps somewhere in the wireless subsystem.

lspci -k includes:
03:00.0 Ethernet controller: Qualcomm Atheros AR242x / AR542x Wireless Network Adapter (PCI-Express) (rev 01)
Subsystem: Foxconn International, Inc. Device e008
Kernel driver in use: ath5k