[PATCH] Partially revert "HID: generic: create one input report per application type"

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

This partially reverts commit f07b3c1da92db108662f99417a212fc1eddc44d1.

It looks like some mice are not correctly treated by
HID_QUIRK_INPUT_PER_APP. Those mice have the following
report descriptor:

0x05, 0x01,                    // Usage Page (Generic Desktop)        0
0x09, 0x02,                    // Usage (Mouse)                       2
0xa1, 0x01,                    // Collection (Application)            4
0x85, 0x01,                    //  Report ID (1)                      6
0x09, 0x01,                    //  Usage (Pointer)                    8
0xa1, 0x00,                    //  Collection (Physical)              10
0x95, 0x05,                    //   Report Count (5)                  12
0x75, 0x01,                    //   Report Size (1)                   14
0x05, 0x09,                    //   Usage Page (Button)               16
0x19, 0x01,                    //   Usage Minimum (1)                 18
0x29, 0x05,                    //   Usage Maximum (5)                 20
0x15, 0x00,                    //   Logical Minimum (0)               22
0x25, 0x01,                    //   Logical Maximum (1)               24
0x81, 0x02,                    //   Input (Data,Var,Abs)              26
...
0xc0,                          //  End Collection                     57
0x85, 0x02,                    //  Report ID (2)                      58
0x09, 0x01,                    //  Usage (Consumer Control)           60
0xa1, 0x00,                    //  Collection (Physical)              62
0x75, 0x0c,                    //   Report Size (12)                  64
0x95, 0x02,                    //   Report Count (2)                  66
0x05, 0x01,                    //   Usage Page (Generic Desktop)      68
0x09, 0x30,                    //   Usage (X)                         70
0x09, 0x31,                    //   Usage (Y)                         72
0x16, 0x01, 0xf8,              //   Logical Minimum (-2047)           74
0x26, 0xff, 0x07,              //   Logical Maximum (2047)            77
0x81, 0x06,                    //   Input (Data,Var,Rel)              80
0xc0,                          //  End Collection                     82
0xc0,                          // End Collection                      83
...

Both the cursor position and the buttons are located in the
same application collection (Mouse) and the kernel should
only create one input device for those.

However, for an undetermined reason, the kernel splits the
device in 2, making systemd not tagging the second mouse
with the coordinates only as a mouse. And then userspace
ignores it which leads to a mouse where only the buttons
are working.

Until the quirk gets properly fixed, we should probably
revert applying it to all of the generic devices and
re-enable it when the root reason has been found.

link: https://bugzilla.kernel.org/show_bug.cgi?id=200847
link: https://bugzilla.kernel.org/show_bug.cgi?id=200849
link: https://bugs.archlinux.org/task/59699
link: https://github.com/NixOS/nixpkgs/issues/45165

Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 drivers/hid/hid-generic.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/drivers/hid/hid-generic.c b/drivers/hid/hid-generic.c
index 3b6eccbc2519..c25b4718de44 100644
--- a/drivers/hid/hid-generic.c
+++ b/drivers/hid/hid-generic.c
@@ -56,20 +56,6 @@ static bool hid_generic_match(struct hid_device *hdev,
 	return true;
 }
 
-static int hid_generic_probe(struct hid_device *hdev,
-			     const struct hid_device_id *id)
-{
-	int ret;
-
-	hdev->quirks |= HID_QUIRK_INPUT_PER_APP;
-
-	ret = hid_parse(hdev);
-	if (ret)
-		return ret;
-
-	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
-}
-
 static const struct hid_device_id hid_table[] = {
 	{ HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY, HID_ANY_ID, HID_ANY_ID) },
 	{ }
@@ -80,7 +66,6 @@ static struct hid_driver hid_generic = {
 	.name = "hid-generic",
 	.id_table = hid_table,
 	.match = hid_generic_match,
-	.probe = hid_generic_probe,
 };
 module_hid_driver(hid_generic);
 
-- 
2.14.3