[3.19.y-ckt stable] Patch "HID: fix hid_ignore_special_drivers module parameter" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    HID: fix hid_ignore_special_drivers module parameter

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 540d2ba7c50355bd2423165d38a9884b4554034e Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires at redhat.com>
Date: Fri, 12 Feb 2016 17:10:37 +0100
Subject: HID: fix hid_ignore_special_drivers module parameter

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 at redhat.com>
Signed-off-by: Jiri Kosina <jkosina at suse.cz>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/hid/hid-core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index d7d965f..53f3ad2 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2540,9 +2540,10 @@ int hid_add_device(struct hid_device *hdev)
 	/*
 	 * 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);
--
2.7.4