HID: logitech-hidpp: rework device validation
authorAndrey Smirnov <andrew.smirnov@gmail.com>
Fri, 18 Oct 2019 04:45:16 +0000 (21:45 -0700)
committerBenjamin Tissoires <benjamin.tissoires@redhat.com>
Fri, 18 Oct 2019 13:29:56 +0000 (15:29 +0200)
commit905d754c53a522aacf806ea1d3e7c929148c1910
tree52cad6a3daddbc6e6ae7d4eae69a1457efc34c1c
parentabdd3d0b344fdf72a4904d09b97bc964d74c4419
HID: logitech-hidpp: rework device validation

G920 device only advertises REPORT_ID_HIDPP_LONG and
REPORT_ID_HIDPP_VERY_LONG in its HID report descriptor, so querying
for REPORT_ID_HIDPP_SHORT with optional=false will always fail and
prevent G920 to be recognized as a valid HID++ device.

To fix this and improve some other aspects, modify
hidpp_validate_device() as follows:

  - Inline the code of hidpp_validate_report() to simplify
    distingushing between non-present and invalid report descriptors

  - Drop the check for id >= HID_MAX_IDS || id < 0 since all of our
    IDs are static and known to satisfy that at compile time

  - Change the algorithms to check all possible report
    types (including very long report) and deem the device as a valid
    HID++ device if it supports at least one

  - Treat invalid report length as a hard stop for the validation
    algorithm, meaning that if any of the supported reports has
    invalid length we assume the worst and treat the device as a
    generic HID device.

  - Fold initialization of hidpp->very_long_report_length into
    hidpp_validate_device() since it already fetches very long report
    length and validates its value

Fixes: fe3ee1ec007b ("HID: logitech-hidpp: allow non HID++ devices to be handled by this module")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204191
Reported-by: Sam Bazely <sambazley@fastmail.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Henrik Rydberg <rydberg@bitmath.org>
Cc: Pierre-Loup A. Griffais <pgriffais@valvesoftware.com>
Cc: Austin Palmer <austinp@valvesoftware.com>
Cc: linux-input@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # 5.2+
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
drivers/hid/hid-logitech-hidpp.c