Hi,
I 've just been looking into what would be needed to support the
one-button backup functionality in my external disk enclosure
and adaptor, because I 'm becoming fed up with windows users
posting in forums that "for me backup is just to plug the
external disk and push its button".
Both devices have JMicron controllers inside (JM20336 for the
dual SATA -> USB enclosure and JM20337/20338 for the adaptor)
and in Windows they are handled by the PCCloneEx software by
some company called Fnet.
These controllers are in a large variety of devices from relatively
small manufacturers and they all use the same software, so
supporting one of them will mean supporting all of the others
as well "for free" from what it seems.
Unfortunately (as you will see from the attached lsusb output)
neither device exposes a HID interface for the button
(like Maxtor Onetouch). Instead, the JMicron people seem to use
special SCSI commands to poll for the button status.
E.g., for the JM20338 we can see in the usbmon log a custom
CDB with command "df" and the result is 0x96 if the button
is pressed and 0x97 if not (looks like the LSB is used, active-low).
For JM20336 it seems slightly more complex but it looks like the
method is essentially the same.
The PCCloneEx software includes a small windows device driver
which I guess is used for this polling since I only see USB
activity on the device when this program is started.
I attach for each chip the following:
* lsusb output
* usbmon output (includes device initialization, 4 presses
of the button and one long hold)
Where in the stack would I need to hack in order to add support
for this functionality?
Thanks,
Pantelis
Attachment:
jm20336.tar.bz2
Description: BZip2 compressed data
Attachment:
jm20338.tar.bz2
Description: BZip2 compressed data
