Hello,

> The ath driver attempts to attach, but fails to configure itself:
> 
> ath0 at cardbus0 function 0
> ath0: unable to alloc memory for 1000 tx descriptors, error 12
> ath0: failed to allocate descriptors: 12

Your system is running out of physically contiguous memory chunks
as it seems.

> Is there a suggestion I can try in a -current kernel to see if it works?

In case you hotplugged the card into a 'live and busy' system,
shut down X / Mozilla / whatever memory eaters and try again.

	-- Jachym Holecek