Re: HID: input: support for misbehaving mice having logical_minimum != 0

Hello folks,

(this is not an actual patch submission; also, this is my first
submission to mainline kernel, so bear with me...)

This is an attempt to fix touchpad handling on Sony Vaio Tap 11.
On that hardware, touchpad is visible as a generic hid-input mouse.
The problem is that kernel does not register mouse button release
events because the hardware reports bogus logical minimum (1) in the
respective field of the HID descriptor. (Sorry for probably wrong
terminology.)

Moreover, the reported logical maximum (5) also disagrees with what
I've seen in other generic USB mice (it's 1 everywhere else), but I
do
not see the logic by which it is determined -- blindly forcing it to
1
system-wide locks me out of the keyboard.

A PoC patch is below that makes touchpad work on that system.
However,
the keyboard/mouse on that system are connected via a WUSB dongle
with
a generic USB VID/PID, so matching via these (as in the rest of
usbhid
quirks) seems inappropriate.

So, I'd appreciate a hint on how to match that hardware for a proper
quirk and what to do with the odd reported logical maximum.

I'm also attaching the output of various debug tools ran before and
after patching.

---
 drivers/hid/hid-input.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index d05f903c7614..f8e780185c8a 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c

@@ -1069,6 +1069,16 @@ static void hidinput_configure_usage(struct

hid_input *hidinput, struct hid_fiel
 	if (usage->type == EV_KEY) {
 		set_bit(EV_MSC, input->evbit);
 		set_bit(MSC_SCAN, input->mscbit);
+
+		if (field->logical_minimum > 0) {
+			hid_err(device, "XXX: EV_KEY logical_minimum
= %d != 0 - updating\n", field->logical_minimum);
+			field->logical_minimum = 0;
+			if (field->logical_maximum != 1) {
+				hid_err(device, "XXX: EV_KEY
logical_maximum = %d != 1 - updating\n", field->logical_maximum);
+				field->logical_maximum = 1;
+			}
+		}
+
 	}
 
 ignore:
-- 
2.13.0

Thanks,