Commit 190d7f02 authored by Benjamin Tissoires's avatar Benjamin Tissoires Committed by Jiri Kosina
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HID: input: do not increment usages when a duplicate is found 



This is something that bothered us from a long time. When hid-input
doesn't know how to map a usage, it uses *_MISC. But there is something
else which increments the usage if the evdev code is already used.

This leads to few issues:
- some devices may have their ABS_X mapped to ABS_Y if they export a bad
  set of usages (see the DragonRise joysticks IIRC -> fixed in a specific
  HID driver)
- *_MISC + N might (will) conflict with other defined axes (my Logitech
  H800 exports some multitouch axes because of that)
- this prevents to freely add some new evdev usages, because "hey, my
  headset will now report ABS_COFFEE, and it's not coffee capable".

So let's try to kill this nonsense, and hope we won't break too many
devices.

I my headset case, the ABS_MISC axes are created because of some
proprietary usages, so we might not break that many devices.

For backward compatibility, a quirk HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE
is created and can be applied to any device that needs this behavior.

Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
Acked-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent e8403b49

drivers/hid/hid-input.c

+31 −2
Original line number Diff line number Diff line
@@ -1100,8 +1100,31 @@ mapped: 


	set_bit(usage->type, input->evbit);



	while (usage->code <= max && test_and_set_bit(usage->code, bit))

		usage->code = find_next_zero_bit(bit, max + 1, usage->code);

	/*

	 * This part is *really* controversial:

	 * - HID aims at being generic so we should do our best to export

	 *   all incoming events

	 * - HID describes what events are, so there is no reason for ABS_X

	 *   to be mapped to ABS_Y

	 * - HID is using *_MISC+N as a default value, but nothing prevents

	 *   *_MISC+N to overwrite a legitimate even, which confuses userspace

	 *   (for instance ABS_MISC + 7 is ABS_MT_SLOT, which has a different

	 *   processing)

	 *

	 * If devices still want to use this (at their own risk), they will

	 * have to use the quirk HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE, but

	 * the default should be a reliable mapping.

	 */

	while (usage->code <= max && test_and_set_bit(usage->code, bit)) {

		if (device->quirks & HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE) {

			usage->code = find_next_zero_bit(bit,

							 max + 1,

							 usage->code);

		} else {

			device->status |= HID_STAT_DUP_DETECTED;

			goto ignore;

		}

	}



	if (usage->code > max)

		goto ignore;
@@ -1611,6 +1634,8 @@ int hidinput_connect(struct hid_device *hid, unsigned int force) 
	INIT_LIST_HEAD(&hid->inputs);

	INIT_WORK(&hid->led_work, hidinput_led_worker);



	hid->status &= ~HID_STAT_DUP_DETECTED;



	if (!force) {

		for (i = 0; i < hid->maxcollection; i++) {

			struct hid_collection *col = &hid->collection[i];
@@ -1677,6 +1702,10 @@ int hidinput_connect(struct hid_device *hid, unsigned int force) 
		goto out_unwind;

	}



	if (hid->status & HID_STAT_DUP_DETECTED)

		hid_dbg(hid,

			"Some usages could not be mapped, please use HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE if this is legitimate.\n");



	return 0;



out_unwind:

include/linux/hid.h

+2 −0
Original line number Diff line number Diff line
@@ -345,6 +345,7 @@ struct hid_item { 
#define HID_QUIRK_SKIP_OUTPUT_REPORT_ID		BIT(17)

#define HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP	BIT(18)

#define HID_QUIRK_HAVE_SPECIAL_DRIVER		BIT(19)

#define HID_QUIRK_INCREMENT_USAGE_ON_DUPLICATE	BIT(20)

#define HID_QUIRK_FULLSPEED_INTERVAL		BIT(28)

#define HID_QUIRK_NO_INIT_REPORTS		BIT(29)

#define HID_QUIRK_NO_IGNORE			BIT(30)
@@ -502,6 +503,7 @@ struct hid_output_fifo { 


#define HID_STAT_ADDED		BIT(0)

#define HID_STAT_PARSED		BIT(1)

#define HID_STAT_DUP_DETECTED	BIT(2)



struct hid_input {

	struct list_head list;

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