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HID: input: do not increment usages when a duplicate is found

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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: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Benjamin Tissoires 2017-12-08 15:28:18 +01:00 committed by Jiri Kosina
parent e8403b493f
commit 190d7f02ce
2 changed files with 33 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

33
drivers/hid/hid-input.c
View file

@ -1100,8 +1100,31 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
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:

2
include/linux/hid.h
View file

@ -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;