"Autosense failed" - I/O stops on SD card reader

[perryh at pluto.rain.com]

Bruce Cran <bruce at cran.org.uk> wrote:
> I've been having problems with a card reader
> (http://www.frontier-electronics.co.za/stor_sdr012.htm) 
> and an 8GB SD card 
...
> (da0:umass-sim0:0:0:0): AutoSense failed
> g_vfs_done():da0s1[READ(offset=6782976, length=36864)]error = 5
> vnode_pager_getpages: I/O read error
> vm_fault: pager read error, pid 2986 (cp)

An 8GB "SD" card is almost certainly an "SDHC" card*, which
AFAICT is not on that reader's list of supported formats.

* SD and SDHC are the same physical size, but SDHC has more
  contacts.