[PATCH] HID: multitouch: do not blindly set EV_KEY or EV_ABS bits

From: Dmitry Torokhov
Date: Tue Jul 11 2017 - 13:02:44 EST


Now that input core insists on having dev->absinfo when device claims to
generate EV_ABS in its dev->evbit, we should not be blindly setting that
bit.

The code in question might have been needed before input_set_abs_params()
started setting EV_ABS in device's evbit, but not anymore, and is now
breaking devices such as SMART SPNL-6075 Touchscreen.

Fixes: 6ecfe51b4082 ("Input: refuse to register absolute devices ...")
Reported-by: Matthias Fend <Matthias.Fend@xxxxxxxxxxxxxx>
Tested-by: Matthias Fend <Matthias.Fend@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---

Jiri, Benjamin, I marked it for stable as it causes regressions in 4.12
reported by users. Please take a look.

drivers/hid/hid-multitouch.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 24d5b6deb571..be5bea15ce52 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -595,16 +595,6 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
return 0;
}

-static int mt_touch_input_mapped(struct hid_device *hdev, struct hid_input *hi,
- struct hid_field *field, struct hid_usage *usage,
- unsigned long **bit, int *max)
-{
- if (usage->type == EV_KEY || usage->type == EV_ABS)
- set_bit(usage->type, hi->input->evbit);
-
- return -1;
-}
-
static int mt_compute_slot(struct mt_device *td, struct input_dev *input)
{
__s32 quirks = td->mtclass.quirks;
@@ -905,8 +895,10 @@ static int mt_input_mapped(struct hid_device *hdev, struct hid_input *hi,
return 0;

if (field->application == HID_DG_TOUCHSCREEN ||
- field->application == HID_DG_TOUCHPAD)
- return mt_touch_input_mapped(hdev, hi, field, usage, bit, max);
+ field->application == HID_DG_TOUCHPAD) {
+ /* We own these mappings, tell hid-input to ignore them */
+ return -1;
+ }

/* let hid-core decide for the others */
return 0;
--
2.13.2.725.g09c95d1e9-goog


--
Dmitry