tree b9c4a4c0f5e4bc6d3e9a95d85a934c6dab9647d8
parent bb22efcb872b8108131a38399ae910dcb0304770
author Nicolas Saenz Julienne <nsaenzjulienne@suse.de> 1553681928 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1559310509 -0700

HID: core: move Usage Page concatenation to Main item

[ Upstream commit 58e75155009cc800005629955d3482f36a1e0eec ]

As seen on some USB wireless keyboards manufactured by Primax, the HID
parser was using some assumptions that are not always true. In this case
it's s the fact that, inside the scope of a main item, an Usage Page
will always precede an Usage.

The spec is not pretty clear as 6.2.2.7 states "Any usage that follows
is interpreted as a Usage ID and concatenated with the Usage Page".
While 6.2.2.8 states "When the parser encounters a main item it
concatenates the last declared Usage Page with a Usage to form a
complete usage value." Being somewhat contradictory it was decided to
match Window's implementation, which follows 6.2.2.8.

In summary, the patch moves the Usage Page concatenation from the local
item parsing function to the main item parsing function.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Terry Junge <terry.junge@poly.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>