[PATCH v9 05/11] HID: asus: move vendor initialization to probe

Antheas Kapenekakis
2025-11-20T09:46:41Z

ROG NKEY devices have multiple HID endpoints, around 3-4. One of those
endpoints has a usage page of 0xff31, and is the one that emits keyboard
shortcuts and controls RGB/backlight. Currently, this driver places
the usage page check under asus_input_mapping and then inits backlight
in asus_input_configured which is unnecessarily complicated and prevents
probe from performing customizations on the vendor endpoint.

Simplify the logic by introducing an is_vendor variable into probe that
checks for usage page 0xff31. Then, use this variable to move backlight
initialization into probe instead of asus_input_configured, and remove
the backlight check from asus_input_mapping.

Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
---
drivers/hid/hid-asus.c | 35 ++++++++++++++++++-----------------
1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index 5149dc7edfc5..3047bc54bf2e 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -47,6 +47,7 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
#define T100CHI_MOUSE_REPORT_ID 0x06
#define FEATURE_REPORT_ID 0x0d
#define INPUT_REPORT_ID 0x5d
+#define HID_USAGE_PAGE_VENDOR 0xff310000
#define FEATURE_KBD_REPORT_ID 0x5a
#define FEATURE_KBD_REPORT_SIZE 64
#define FEATURE_KBD_LED_REPORT_ID1 0x5d
@@ -126,7 +127,6 @@ struct asus_drvdata {
struct input_dev *tp_kbd_input;
struct asus_kbd_leds *kbd_backlight;
const struct asus_touchpad_info *tp;
- bool enable_backlight;
struct power_supply *battery;
struct power_supply_desc battery_desc;
int battery_capacity;
@@ -317,7 +317,7 @@ static int asus_e1239t_event(struct asus_drvdata *drvdat, u8 *data, int size)
static int asus_event(struct hid_device *hdev, struct hid_field *field,
struct hid_usage *usage, __s32 value)
{
- if ((usage->hid & HID_USAGE_PAGE) == 0xff310000 &&
+ if ((usage->hid & HID_USAGE_PAGE) == HID_USAGE_PAGE_VENDOR &&
(usage->hid & HID_USAGE) != 0x00 &&
(usage->hid & HID_USAGE) != 0xff && !usage->type) {
hid_warn(hdev, "Unmapped Asus vendor usagepage code 0x%02x\n",
@@ -942,11 +942,6 @@ static int asus_input_configured(struct hid_device *hdev, struct hid_input *hi)

drvdata->input = input;

- if (drvdata->enable_backlight &&
- !asus_kbd_wmi_led_control_present(hdev) &&
- asus_kbd_register_leds(hdev))
- hid_warn(hdev, "Failed to initialize backlight.\n");
-
return 0;
}

@@ -1019,15 +1014,6 @@ static int asus_input_mapping(struct hid_device *hdev,
return -1;
}

- /*
- * Check and enable backlight only on devices with UsagePage ==
- * 0xff31 to avoid initializing the keyboard firmware multiple
- * times on devices with multiple HID descriptors but same
- * PID/VID.
- */
- if (drvdata->quirks & QUIRK_USE_KBD_BACKLIGHT)
- drvdata->enable_backlight = true;
-
set_bit(EV_REP, hi->input->evbit);
return 1;
}
@@ -1144,8 +1130,11 @@ static int __maybe_unused asus_reset_resume(struct hid_device *hdev)

static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
- int ret;
+ struct hid_report_enum *rep_enum;
struct asus_drvdata *drvdata;
+ struct hid_report *rep;
+ bool is_vendor = false;
+ int ret;

drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
if (drvdata == NULL) {
@@ -1229,12 +1218,24 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
return ret;
}

+ /* Check for vendor for RGB init and handle generic devices properly. */
+ rep_enum = &hdev->report_enum[HID_INPUT_REPORT];
+ list_for_each_entry(rep, &rep_enum->report_list, list) {
+ if ((rep->application & HID_USAGE_PAGE) == HID_USAGE_PAGE_VENDOR)
+ is_vendor = true;
+ }
+
ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
if (ret) {
hid_err(hdev, "Asus hw start failed: %d\n", ret);
return ret;
}

+ if (is_vendor && (drvdata->quirks & QUIRK_USE_KBD_BACKLIGHT) &&
+ !asus_kbd_wmi_led_control_present(hdev) &&
+ asus_kbd_register_leds(hdev))
+ hid_warn(hdev, "Failed to initialize backlight.\n");
+
/*
* Check that input registration succeeded. Checking that
* HID_CLAIMED_INPUT is set prevents a UAF when all input devices
--
2.52.0