[PATCH 4.4 091/210] HID: fix hid_ignore_special_drivers module parameter

From: Greg Kroah-Hartman
Date: Sun Apr 10 2016 - 16:01:43 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>

commit 4392bf333388cabdad5afe5b1500002d7b9c318e upstream.

hid_ignore_special_drivers works fine until hid_scan_report autodetects and
reassign devices (for hid-multitouch, hid-microsoft and hid-rmi).

Simplify the handling of the parameter: if it is there, use hid-generic, no
matter what, and if not, scan the device or rely on the hid_have_special_driver
table.

This was detected while trying to disable hid-multitouch on a Surface Pro cover
which prevented to use the keyboard.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/hid/hid-core.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2616,9 +2616,10 @@ int hid_add_device(struct hid_device *hd
/*
* Scan generic devices for group information
*/
- if (hid_ignore_special_drivers ||
- (!hdev->group &&
- !hid_match_id(hdev, hid_have_special_driver))) {
+ if (hid_ignore_special_drivers) {
+ hdev->group = HID_GROUP_GENERIC;
+ } else if (!hdev->group &&
+ !hid_match_id(hdev, hid_have_special_driver)) {
ret = hid_scan_report(hdev);
if (ret)
hid_warn(hdev, "bad device descriptor (%d)\n", ret);