[PATCH 4.19 46/86] HID: apple: Disable Fn-key key-re-mapping on clone keyboards

Greg Kroah-Hartman
2020-07-27T14:10:52Z

From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit a5d81646fa294eed57786a9310b06ca48902adf8 ]

The Maxxter KB-BT-001 Bluetooth keyboard, which looks somewhat like the
Apple Wireless Keyboard, is using the vendor and product IDs (05AC:0239)
of the Apple Wireless Keyboard (2009 ANSI version) <sigh>.

But its F1 - F10 keys are marked as sending F1 - F10, not the special
functions hid-apple.c maps them too; and since its descriptors do not
contain the HID_UP_CUSTOM | 0x0003 usage apple-hid looks for for the
Fn-key, apple_setup_input() never gets called, so F1 - F6 are mapped
to key-codes which have not been set in the keybit array causing them
to not send any events at all.

The lack of a usage code matching the Fn key in the clone is actually
useful as this allows solving this problem in a generic way.

This commits adds a fn_found flag and it adds a input_configured
callback which checks if this flag is set once all usages have been
mapped. If it is not set, then assume this is a clone and clear the
quirks bitmap so that the hid-apple code does not add any special
handling to this keyboard.

This fixes F1 - F6 not sending anything at all and F7 - F12 sending
the wrong codes on the Maxxter KB-BT-001 Bluetooth keyboard and on
similar clones.

Cc: Joao Moreno <mail@joaomoreno.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/hid-apple.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/drivers/hid/hid-apple.c b/drivers/hid/hid-apple.c
index 8ab8f2350bbcd..b58ab769aa7b3 100644
--- a/drivers/hid/hid-apple.c
+++ b/drivers/hid/hid-apple.c
@@ -57,6 +57,7 @@ MODULE_PARM_DESC(swap_opt_cmd, "Swap the Option (\"Alt\") and Command (\"Flag\")
struct apple_sc {
unsigned long quirks;
unsigned int fn_on;
+ unsigned int fn_found;
DECLARE_BITMAP(pressed_numlock, KEY_CNT);
};

@@ -342,12 +343,15 @@ static int apple_input_mapping(struct hid_device *hdev, struct hid_input *hi,
struct hid_field *field, struct hid_usage *usage,
unsigned long **bit, int *max)
{
+ struct apple_sc *asc = hid_get_drvdata(hdev);
+
if (usage->hid == (HID_UP_CUSTOM | 0x0003) ||
usage->hid == (HID_UP_MSVENDOR | 0x0003) ||
usage->hid == (HID_UP_HPVENDOR2 | 0x0003)) {
/* The fn key on Apple USB keyboards */
set_bit(EV_REP, hi->input->evbit);
hid_map_usage_clear(hi, usage, bit, max, EV_KEY, KEY_FN);
+ asc->fn_found = true;
apple_setup_input(hi->input);
return 1;
}
@@ -374,6 +378,19 @@ static int apple_input_mapped(struct hid_device *hdev, struct hid_input *hi,
return 0;
}

+static int apple_input_configured(struct hid_device *hdev,
+ struct hid_input *hidinput)
+{
+ struct apple_sc *asc = hid_get_drvdata(hdev);
+
+ if ((asc->quirks & APPLE_HAS_FN) && !asc->fn_found) {
+ hid_info(hdev, "Fn key not found (Apple Wireless Keyboard clone?), disabling Fn key handling\n");
+ asc->quirks = 0;
+ }
+
+ return 0;
+}
+
static int apple_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
@@ -588,6 +605,7 @@ static struct hid_driver apple_driver = {
.event = apple_event,
.input_mapping = apple_input_mapping,
.input_mapped = apple_input_mapped,
+ .input_configured = apple_input_configured,
};
module_hid_driver(apple_driver);

--
2.25.1