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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-30 09:22:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-30 09:22:00 -0700
commit034dd340b08be1f2f0477ad16131d609f9dbd53c (patch)
tree2536f4b2d7893ccd916b5abdf3c454ad6edc03c2 /drivers/hid/hid-elan.c
downloadlinux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.tar.gz
linux-stable-034dd340b08be1f2f0477ad16131d609f9dbd53c.zip
Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted
Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure
Diffstat (limited to 'drivers/hid/hid-elan.c')
-rw-r--r--drivers/hid/hid-elan.c534
1 files changed, 534 insertions, 0 deletions
diff --git a/drivers/hid/hid-elan.c b/drivers/hid/hid-elan.c
new file mode 100644
index 000000000..0190ad567
--- /dev/null
+++ b/drivers/hid/hid-elan.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HID Driver for ELAN Touchpad
+ *
+ * Currently only supports touchpad found on HP Pavilion X2 10
+ *
+ * Copyright (c) 2016 Alexandrov Stanislav <neko@nya.ai>
+ */
+
+#include <linux/hid.h>
+#include <linux/input/mt.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+#define ELAN_MT_I2C 0x5d
+#define ELAN_SINGLE_FINGER 0x81
+#define ELAN_MT_FIRST_FINGER 0x82
+#define ELAN_MT_SECOND_FINGER 0x83
+#define ELAN_INPUT_REPORT_SIZE 8
+#define ELAN_I2C_REPORT_SIZE 32
+#define ELAN_FINGER_DATA_LEN 5
+#define ELAN_MAX_FINGERS 5
+#define ELAN_MAX_PRESSURE 255
+#define ELAN_TP_USB_INTF 1
+
+#define ELAN_FEATURE_REPORT 0x0d
+#define ELAN_FEATURE_SIZE 5
+#define ELAN_PARAM_MAX_X 6
+#define ELAN_PARAM_MAX_Y 7
+#define ELAN_PARAM_RES 8
+
+#define ELAN_MUTE_LED_REPORT 0xBC
+#define ELAN_LED_REPORT_SIZE 8
+
+#define ELAN_HAS_LED BIT(0)
+
+struct elan_drvdata {
+ struct input_dev *input;
+ u8 prev_report[ELAN_INPUT_REPORT_SIZE];
+ struct led_classdev mute_led;
+ u8 mute_led_state;
+ u16 max_x;
+ u16 max_y;
+ u16 res_x;
+ u16 res_y;
+};
+
+static int is_not_elan_touchpad(struct hid_device *hdev)
+{
+ if (hid_is_usb(hdev)) {
+ struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+
+ return (intf->altsetting->desc.bInterfaceNumber !=
+ ELAN_TP_USB_INTF);
+ }
+
+ return 0;
+}
+
+static int elan_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+ struct hid_field *field, struct hid_usage *usage,
+ unsigned long **bit, int *max)
+{
+ if (is_not_elan_touchpad(hdev))
+ return 0;
+
+ if (field->report->id == ELAN_SINGLE_FINGER ||
+ field->report->id == ELAN_MT_FIRST_FINGER ||
+ field->report->id == ELAN_MT_SECOND_FINGER ||
+ field->report->id == ELAN_MT_I2C)
+ return -1;
+
+ return 0;
+}
+
+static int elan_get_device_param(struct hid_device *hdev,
+ unsigned char *dmabuf, unsigned char param)
+{
+ int ret;
+
+ dmabuf[0] = ELAN_FEATURE_REPORT;
+ dmabuf[1] = 0x05;
+ dmabuf[2] = 0x03;
+ dmabuf[3] = param;
+ dmabuf[4] = 0x01;
+
+ ret = hid_hw_raw_request(hdev, ELAN_FEATURE_REPORT, dmabuf,
+ ELAN_FEATURE_SIZE, HID_FEATURE_REPORT,
+ HID_REQ_SET_REPORT);
+ if (ret != ELAN_FEATURE_SIZE) {
+ hid_err(hdev, "Set report error for parm %d: %d\n", param, ret);
+ return ret;
+ }
+
+ ret = hid_hw_raw_request(hdev, ELAN_FEATURE_REPORT, dmabuf,
+ ELAN_FEATURE_SIZE, HID_FEATURE_REPORT,
+ HID_REQ_GET_REPORT);
+ if (ret != ELAN_FEATURE_SIZE) {
+ hid_err(hdev, "Get report error for parm %d: %d\n", param, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static unsigned int elan_convert_res(char val)
+{
+ /*
+ * (value from firmware) * 10 + 790 = dpi
+ * dpi * 10 / 254 = dots/mm
+ */
+ return (val * 10 + 790) * 10 / 254;
+}
+
+static int elan_get_device_params(struct hid_device *hdev)
+{
+ struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
+ unsigned char *dmabuf;
+ int ret;
+
+ dmabuf = kmalloc(ELAN_FEATURE_SIZE, GFP_KERNEL);
+ if (!dmabuf)
+ return -ENOMEM;
+
+ ret = elan_get_device_param(hdev, dmabuf, ELAN_PARAM_MAX_X);
+ if (ret)
+ goto err;
+
+ drvdata->max_x = (dmabuf[4] << 8) | dmabuf[3];
+
+ ret = elan_get_device_param(hdev, dmabuf, ELAN_PARAM_MAX_Y);
+ if (ret)
+ goto err;
+
+ drvdata->max_y = (dmabuf[4] << 8) | dmabuf[3];
+
+ ret = elan_get_device_param(hdev, dmabuf, ELAN_PARAM_RES);
+ if (ret)
+ goto err;
+
+ drvdata->res_x = elan_convert_res(dmabuf[3]);
+ drvdata->res_y = elan_convert_res(dmabuf[4]);
+
+err:
+ kfree(dmabuf);
+ return ret;
+}
+
+static int elan_input_configured(struct hid_device *hdev, struct hid_input *hi)
+{
+ int ret;
+ struct input_dev *input;
+ struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
+
+ if (is_not_elan_touchpad(hdev))
+ return 0;
+
+ ret = elan_get_device_params(hdev);
+ if (ret)
+ return ret;
+
+ input = devm_input_allocate_device(&hdev->dev);
+ if (!input)
+ return -ENOMEM;
+
+ input->name = "Elan Touchpad";
+ input->phys = hdev->phys;
+ input->uniq = hdev->uniq;
+ input->id.bustype = hdev->bus;
+ input->id.vendor = hdev->vendor;
+ input->id.product = hdev->product;
+ input->id.version = hdev->version;
+ input->dev.parent = &hdev->dev;
+
+ input_set_abs_params(input, ABS_MT_POSITION_X, 0, drvdata->max_x,
+ 0, 0);
+ input_set_abs_params(input, ABS_MT_POSITION_Y, 0, drvdata->max_y,
+ 0, 0);
+ input_set_abs_params(input, ABS_MT_PRESSURE, 0, ELAN_MAX_PRESSURE,
+ 0, 0);
+
+ __set_bit(BTN_LEFT, input->keybit);
+ __set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
+
+ ret = input_mt_init_slots(input, ELAN_MAX_FINGERS, INPUT_MT_POINTER);
+ if (ret) {
+ hid_err(hdev, "Failed to init elan MT slots: %d\n", ret);
+ return ret;
+ }
+
+ input_abs_set_res(input, ABS_X, drvdata->res_x);
+ input_abs_set_res(input, ABS_Y, drvdata->res_y);
+
+ ret = input_register_device(input);
+ if (ret) {
+ hid_err(hdev, "Failed to register elan input device: %d\n",
+ ret);
+ input_mt_destroy_slots(input);
+ return ret;
+ }
+
+ drvdata->input = input;
+
+ return 0;
+}
+
+static void elan_report_mt_slot(struct elan_drvdata *drvdata, u8 *data,
+ unsigned int slot_num)
+{
+ struct input_dev *input = drvdata->input;
+ int x, y, p;
+
+ bool active = !!data;
+
+ input_mt_slot(input, slot_num);
+ input_mt_report_slot_state(input, MT_TOOL_FINGER, active);
+ if (active) {
+ x = ((data[0] & 0xF0) << 4) | data[1];
+ y = drvdata->max_y -
+ (((data[0] & 0x07) << 8) | data[2]);
+ p = data[4];
+
+ input_report_abs(input, ABS_MT_POSITION_X, x);
+ input_report_abs(input, ABS_MT_POSITION_Y, y);
+ input_report_abs(input, ABS_MT_PRESSURE, p);
+ }
+}
+
+static void elan_usb_report_input(struct elan_drvdata *drvdata, u8 *data)
+{
+ int i;
+ struct input_dev *input = drvdata->input;
+
+ /*
+ * There is 3 types of reports: for single touch,
+ * for multitouch - first finger and for multitouch - second finger
+ *
+ * packet structure for ELAN_SINGLE_FINGER and ELAN_MT_FIRST_FINGER:
+ *
+ * byte 1: 1 0 0 0 0 0 0 1 // 0x81 or 0x82
+ * byte 2: 0 0 0 0 0 0 0 0 // looks like unused
+ * byte 3: f5 f4 f3 f2 f1 0 0 L
+ * byte 4: x12 x11 x10 x9 0? y11 y10 y9
+ * byte 5: x8 x7 x6 x5 x4 x3 x2 x1
+ * byte 6: y8 y7 y6 y5 y4 y3 y2 y1
+ * byte 7: sy4 sy3 sy2 sy1 sx4 sx3 sx2 sx1
+ * byte 8: p8 p7 p6 p5 p4 p3 p2 p1
+ *
+ * packet structure for ELAN_MT_SECOND_FINGER:
+ *
+ * byte 1: 1 0 0 0 0 0 1 1 // 0x83
+ * byte 2: x12 x11 x10 x9 0 y11 y10 y9
+ * byte 3: x8 x7 x6 x5 x4 x3 x2 x1
+ * byte 4: y8 y7 y6 y5 y4 y3 y2 y1
+ * byte 5: sy4 sy3 sy2 sy1 sx4 sx3 sx2 sx1
+ * byte 6: p8 p7 p6 p5 p4 p3 p2 p1
+ * byte 7: 0 0 0 0 0 0 0 0
+ * byte 8: 0 0 0 0 0 0 0 0
+ *
+ * f5-f1: finger touch bits
+ * L: clickpad button
+ * sy / sx: finger width / height expressed in traces, the total number
+ * of traces can be queried by doing a HID_REQ_SET_REPORT
+ * { 0x0d, 0x05, 0x03, 0x05, 0x01 } followed by a GET, in the
+ * returned buf, buf[3]=no-x-traces, buf[4]=no-y-traces.
+ * p: pressure
+ */
+
+ if (data[0] == ELAN_SINGLE_FINGER) {
+ for (i = 0; i < ELAN_MAX_FINGERS; i++) {
+ if (data[2] & BIT(i + 3))
+ elan_report_mt_slot(drvdata, data + 3, i);
+ else
+ elan_report_mt_slot(drvdata, NULL, i);
+ }
+ input_report_key(input, BTN_LEFT, data[2] & 0x01);
+ }
+ /*
+ * When touched with two fingers Elan touchpad will emit two HID reports
+ * first is ELAN_MT_FIRST_FINGER and second is ELAN_MT_SECOND_FINGER
+ * we will save ELAN_MT_FIRST_FINGER report and wait for
+ * ELAN_MT_SECOND_FINGER to finish multitouch
+ */
+ if (data[0] == ELAN_MT_FIRST_FINGER) {
+ memcpy(drvdata->prev_report, data,
+ sizeof(drvdata->prev_report));
+ return;
+ }
+
+ if (data[0] == ELAN_MT_SECOND_FINGER) {
+ int first = 0;
+ u8 *prev_report = drvdata->prev_report;
+
+ if (prev_report[0] != ELAN_MT_FIRST_FINGER)
+ return;
+
+ for (i = 0; i < ELAN_MAX_FINGERS; i++) {
+ if (prev_report[2] & BIT(i + 3)) {
+ if (!first) {
+ first = 1;
+ elan_report_mt_slot(drvdata, prev_report + 3, i);
+ } else {
+ elan_report_mt_slot(drvdata, data + 1, i);
+ }
+ } else {
+ elan_report_mt_slot(drvdata, NULL, i);
+ }
+ }
+ input_report_key(input, BTN_LEFT, prev_report[2] & 0x01);
+ }
+
+ input_mt_sync_frame(input);
+ input_sync(input);
+}
+
+static void elan_i2c_report_input(struct elan_drvdata *drvdata, u8 *data)
+{
+ struct input_dev *input = drvdata->input;
+ u8 *finger_data;
+ int i;
+
+ /*
+ * Elan MT touchpads in i2c mode send finger data in the same format
+ * as in USB mode, but then with all fingers in a single packet.
+ *
+ * packet structure for ELAN_MT_I2C:
+ *
+ * byte 1: 1 0 0 1 1 1 0 1 // 0x5d
+ * byte 2: f5 f4 f3 f2 f1 0 0 L
+ * byte 3: x12 x11 x10 x9 0? y11 y10 y9
+ * byte 4: x8 x7 x6 x5 x4 x3 x2 x1
+ * byte 5: y8 y7 y6 y5 y4 y3 y2 y1
+ * byte 6: sy4 sy3 sy2 sy1 sx4 sx3 sx2 sx1
+ * byte 7: p8 p7 p6 p5 p4 p3 p2 p1
+ * byte 8-12: Same as byte 3-7 for second finger down
+ * byte 13-17: Same as byte 3-7 for third finger down
+ * byte 18-22: Same as byte 3-7 for fourth finger down
+ * byte 23-27: Same as byte 3-7 for fifth finger down
+ */
+
+ finger_data = data + 2;
+ for (i = 0; i < ELAN_MAX_FINGERS; i++) {
+ if (data[1] & BIT(i + 3)) {
+ elan_report_mt_slot(drvdata, finger_data, i);
+ finger_data += ELAN_FINGER_DATA_LEN;
+ } else {
+ elan_report_mt_slot(drvdata, NULL, i);
+ }
+ }
+
+ input_report_key(input, BTN_LEFT, data[1] & 0x01);
+ input_mt_sync_frame(input);
+ input_sync(input);
+}
+
+static int elan_raw_event(struct hid_device *hdev,
+ struct hid_report *report, u8 *data, int size)
+{
+ struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
+
+ if (is_not_elan_touchpad(hdev))
+ return 0;
+
+ if (data[0] == ELAN_SINGLE_FINGER ||
+ data[0] == ELAN_MT_FIRST_FINGER ||
+ data[0] == ELAN_MT_SECOND_FINGER) {
+ if (size == ELAN_INPUT_REPORT_SIZE) {
+ elan_usb_report_input(drvdata, data);
+ return 1;
+ }
+ }
+
+ if (data[0] == ELAN_MT_I2C && size == ELAN_I2C_REPORT_SIZE) {
+ elan_i2c_report_input(drvdata, data);
+ return 1;
+ }
+
+ return 0;
+}
+
+static int elan_start_multitouch(struct hid_device *hdev)
+{
+ int ret;
+
+ /*
+ * This byte sequence will enable multitouch mode and disable
+ * mouse emulation
+ */
+ static const unsigned char buf[] = { 0x0D, 0x00, 0x03, 0x21, 0x00 };
+ unsigned char *dmabuf = kmemdup(buf, sizeof(buf), GFP_KERNEL);
+
+ if (!dmabuf)
+ return -ENOMEM;
+
+ ret = hid_hw_raw_request(hdev, dmabuf[0], dmabuf, sizeof(buf),
+ HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+
+ kfree(dmabuf);
+
+ if (ret != sizeof(buf)) {
+ hid_err(hdev, "Failed to start multitouch: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int elan_mute_led_set_brigtness(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ int ret;
+ u8 led_state;
+ struct device *dev = led_cdev->dev->parent;
+ struct hid_device *hdev = to_hid_device(dev);
+ struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
+
+ unsigned char *dmabuf = kzalloc(ELAN_LED_REPORT_SIZE, GFP_KERNEL);
+
+ if (!dmabuf)
+ return -ENOMEM;
+
+ led_state = !!value;
+
+ dmabuf[0] = ELAN_MUTE_LED_REPORT;
+ dmabuf[1] = 0x02;
+ dmabuf[2] = led_state;
+
+ ret = hid_hw_raw_request(hdev, dmabuf[0], dmabuf, ELAN_LED_REPORT_SIZE,
+ HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+
+ kfree(dmabuf);
+
+ if (ret != ELAN_LED_REPORT_SIZE) {
+ if (ret != -ENODEV)
+ hid_err(hdev, "Failed to set mute led brightness: %d\n", ret);
+ return ret < 0 ? ret : -EIO;
+ }
+
+ drvdata->mute_led_state = led_state;
+ return 0;
+}
+
+static int elan_init_mute_led(struct hid_device *hdev)
+{
+ struct elan_drvdata *drvdata = hid_get_drvdata(hdev);
+ struct led_classdev *mute_led = &drvdata->mute_led;
+
+ mute_led->name = "elan:red:mute";
+ mute_led->default_trigger = "audio-mute";
+ mute_led->brightness_set_blocking = elan_mute_led_set_brigtness;
+ mute_led->max_brightness = LED_ON;
+ mute_led->flags = LED_HW_PLUGGABLE;
+ mute_led->dev = &hdev->dev;
+
+ return devm_led_classdev_register(&hdev->dev, mute_led);
+}
+
+static int elan_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+ int ret;
+ struct elan_drvdata *drvdata;
+
+ drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+
+ if (!drvdata)
+ return -ENOMEM;
+
+ hid_set_drvdata(hdev, drvdata);
+
+ ret = hid_parse(hdev);
+ if (ret) {
+ hid_err(hdev, "Hid Parse failed\n");
+ return ret;
+ }
+
+ ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+ if (ret) {
+ hid_err(hdev, "Hid hw start failed\n");
+ return ret;
+ }
+
+ if (is_not_elan_touchpad(hdev))
+ return 0;
+
+ if (!drvdata->input) {
+ hid_err(hdev, "Input device is not registered\n");
+ ret = -ENAVAIL;
+ goto err;
+ }
+
+ ret = elan_start_multitouch(hdev);
+ if (ret)
+ goto err;
+
+ if (id->driver_data & ELAN_HAS_LED) {
+ ret = elan_init_mute_led(hdev);
+ if (ret)
+ goto err;
+ }
+
+ return 0;
+err:
+ hid_hw_stop(hdev);
+ return ret;
+}
+
+static const struct hid_device_id elan_devices[] = {
+ { HID_USB_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_HP_X2),
+ .driver_data = ELAN_HAS_LED },
+ { HID_USB_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_HP_X2_10_COVER),
+ .driver_data = ELAN_HAS_LED },
+ { HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_TOSHIBA_CLICK_L9W) },
+ { HID_I2C_DEVICE(USB_VENDOR_ID_ELAN, USB_DEVICE_ID_SB974D) },
+ { }
+};
+MODULE_DEVICE_TABLE(hid, elan_devices);
+
+static struct hid_driver elan_driver = {
+ .name = "elan",
+ .id_table = elan_devices,
+ .input_mapping = elan_input_mapping,
+ .input_configured = elan_input_configured,
+ .raw_event = elan_raw_event,
+ .probe = elan_probe,
+};
+
+module_hid_driver(elan_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alexandrov Stanislav");
+MODULE_DESCRIPTION("Driver for HID ELAN Touchpads");