On Sun, 15 Dec 2013, Mark Lord wrote:

The recent update 08ec2dcc3527a20c619aca2fb36f800908256bac
 "Merge branches 'for-3.11/multitouch', 'for-3.11/sony' and 'for-3.11/upstream' into for-linus"
included an unexpected change to the return code handing for ->raw_event() calls.

A HID driver's raw_event() method previously could return these values:
   0 --> keep processing.
   1 --> no further processing required.
   <0 --> error.

Now, "1" and "0" are both treated as "keep processing",
so a lower level HID driver has to return a negative error code
to achieve the "no further processing required" state.

Was this intentional?  Doesn't that have side-effects for some drivers?

Hi Mark,

this was intentional -- please see commit b1a1442a23 and discussion here: 
https://lkml.org/lkml/2013/3/21/591

If you have any other concerns, please let me know.

-- 
Jiri Kosina
SUSE Labs