[PATCH] platform/x86: bitland-mifs-wmi: add TM2424 thin-ultrabook perf-mode quirk
From: kento
Date: Sun Aug 16 2026 - 18:09:03 EST
From: KentoNion <mrKentoNion@xxxxxxxxx>
The in-tree mapping of platform_profile to sequential cmd 0x08 values
0..3 matches Tongfang/Redmi G gaming firmware. Xiaomi Book Pro 14 (DMI
board_name TM2424) uses a different encoding:
Quiet=0x02, Turbo=0x03, Full-speed=0x04, Auto=0x09, Eco=0x0A
On this SKU the DC-barrel-jack gate also wrongly blocks Performance:
the machine only charges over USB-C. Full-speed is still rejected by
firmware on battery (status byte != 0x80), so honour that status and
fall back to Turbo.
hwmon, keyboard LED and gpu_mode/kb_mode/fan_boost are unimplemented
on this firmware (0xE0); skip registering them.
Tested on Xiaomi Book Pro 14 2026 (TM2424-77080): performance on AC
holds ~50W package power.
Signed-off-by: KentoNion <mrKentoNion@xxxxxxxxx>
---
.../wmi/devices/bitland-mifs-wmi.rst | 22 +-
drivers/platform/x86/bitland-mifs-wmi.c | 190 +++++++++++++++++-
2 files changed, 196 insertions(+), 16 deletions(-)
diff --git a/Documentation/wmi/devices/bitland-mifs-wmi.rst b/Documentation/wmi/devices/bitland-mifs-wmi.rst
index 9e86ecc2993c..99799fd1b09c 100644
--- a/Documentation/wmi/devices/bitland-mifs-wmi.rst
+++ b/Documentation/wmi/devices/bitland-mifs-wmi.rst
@@ -93,8 +93,11 @@ The following Command IDs are used in the third byte of the buffer:
+----------+-----------------------+------------------------------------------+
| ID | Name | Values / Description |
+==========+=======================+==========================================+
-| 8 | SystemPerMode | 0: Balance, 1: Performance, 2: Quiet, |
-| | | 3: Full-speed |
+| 8 | SystemPerMode | Gaming line: 0 Balance, 1 Performance, |
+| | | 2 Quiet, 3 Full-speed. |
+| | | Thin-ultrabook (TM2424): 0x02 Quiet, |
+| | | 0x03 Turbo, 0x04 Full-speed, 0x09 Auto, |
+| | | 0x0A Eco. |
+----------+-----------------------+------------------------------------------+
| 9 | GPUMode | 0: Hybrid, 1: Discrete, 2: UMA |
+----------+-----------------------+------------------------------------------+
@@ -188,11 +191,18 @@ Performance Modes
-----------------
Changing the performance mode via Command ID 0x08 (SystemPerMode) affects the
power limits (PL1/PL2) and fan curves managed by the Embedded Controller (EC).
-Note that the "Full-speed" and "Performance" mode (1, 3) is typically only
-available when the system is connected to a DC power source (not USB-C/PD).
-In the driver implementation, switch to performance/full-speed mode without
-DC power connected will throw the EOPNOTSUPP error.
+Two firmware encodings exist:
+
+* Gaming line (Tongfang/Redmi G): sequential values 0..3. Full-speed and
+ Performance typically require a DC barrel jack; the driver returns
+ ``-EOPNOTSUPP`` otherwise.
+* Thin-ultrabook line (Xiaomi Book Pro 14, DMI ``board_name=TM2424``):
+ Quiet=0x02, Turbo=0x03, Full-speed=0x04, Auto=0x09, Eco=0x0A. These
+ machines charge over USB-C only. Full-speed is still rejected by firmware
+ on battery (status byte != 0x80); the driver then falls back to Turbo.
+
+The firmware status byte is ``OutData[1]`` (0x80 accepted / supported).
Graphics Switching
------------------
diff --git a/drivers/platform/x86/bitland-mifs-wmi.c b/drivers/platform/x86/bitland-mifs-wmi.c
index b0d06a80e89e..e255fd3b30fb 100644
--- a/drivers/platform/x86/bitland-mifs-wmi.c
+++ b/drivers/platform/x86/bitland-mifs-wmi.c
@@ -2,7 +2,11 @@
/*
* Linux driver for Bitland notebooks.
*
- * Copyright (C) 2026 2 Mingyou Chen <qby140326@xxxxxxxxx>
+ * Copyright (C) 2026 Mingyou Chen <qby140326@xxxxxxxxx>
+ *
+ * Thin-ultrabook firmware (Xiaomi Book Pro 14 / TM2424) uses a different
+ * cmd 0x08 encoding than the gaming line. Detected via DMI; other Bitland
+ * hardware keeps the original 0..3 mapping.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -14,6 +18,7 @@
#include <linux/dev_printk.h>
#include <linux/device.h>
#include <linux/device/devres.h>
+#include <linux/dmi.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/init.h>
@@ -38,6 +43,9 @@
#define BITLAND_MIFS_GUID "B60BFB48-3E5B-49E4-A0E9-8CFFE1B3434B"
#define BITLAND_EVENT_GUID "46C93E13-EE9B-4262-8488-563BCA757FEF"
+/* Firmware status in output.operation (wire OUT[1]): request accepted. */
+#define MIFS_STATUS_OK 0x80
+
enum bitland_mifs_operation {
WMI_METHOD_GET = 250,
WMI_METHOD_SET = 251,
@@ -73,6 +81,15 @@ enum bitland_mifs_power_profile {
WMI_PP_FULL_SPEED = 3,
};
+/* cmd 0x08 values on the thin-ultrabook firmware line (TM2424). */
+enum bitland_mifs_thin_perf_mode {
+ WMI_THIN_QUIET = 0x02,
+ WMI_THIN_TURBO = 0x03,
+ WMI_THIN_FULL_SPEED = 0x04,
+ WMI_THIN_AUTO = 0x09,
+ WMI_THIN_ECO = 0x0A,
+};
+
enum bitland_mifs_event_id {
WMI_EVENT_RESERVED_1 = 1,
WMI_EVENT_RESERVED_2 = 2,
@@ -123,7 +140,7 @@ struct bitland_mifs_input {
struct bitland_mifs_output {
u8 reserved1;
- u8 operation;
+ u8 operation; /* firmware status on replies: MIFS_STATUS_OK = accepted/supported */
u8 reserved2;
u8 function;
u8 data[28];
@@ -159,6 +176,18 @@ struct bitland_mifs_wmi_data {
struct device *hwmon_dev;
struct device *pp_dev;
enum platform_profile_option saved_profile;
+ bool thin_ultrabook; /* DMI quirk: TM2424 thin-ultrabook firmware */
+};
+
+static const struct dmi_system_id bitland_mifs_thin_ultrabook_table[] = {
+ {
+ .ident = "Xiaomi Book Pro 14 (TM2424)",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "XIAOMI"),
+ DMI_MATCH(DMI_BOARD_NAME, "TM2424"),
+ },
+ },
+ { }
};
static int bitland_mifs_wmi_call(struct bitland_mifs_wmi_data *data,
@@ -167,23 +196,118 @@ static int bitland_mifs_wmi_call(struct bitland_mifs_wmi_data *data,
{
struct wmi_buffer in_buf = { .length = sizeof(*input), .data = (void *)input };
struct wmi_buffer out_buf = { 0 };
+ struct bitland_mifs_output local_output;
+ struct bitland_mifs_output *dest = output ? output : &local_output;
int ret;
guard(mutex)(&data->lock);
- if (!output)
- return wmidev_invoke_procedure(data->wdev, 0, 1, &in_buf);
-
- ret = wmidev_invoke_method(data->wdev, 0, 1, &in_buf, &out_buf, sizeof(*output));
+ /*
+ * Always parse the reply so SET can check output.operation
+ * (firmware status) instead of fire-and-forget.
+ */
+ ret = wmidev_invoke_method(data->wdev, 0, 1, &in_buf, &out_buf, sizeof(*dest));
if (ret)
return ret;
- memcpy(output, out_buf.data, sizeof(*output));
+ memcpy(dest, out_buf.data, sizeof(*dest));
kfree(out_buf.data);
return 0;
}
+/* --- Thin-ultrabook (TM2424) perf mode --- */
+
+static int bitland_thin_wmi_perf_set(struct bitland_mifs_wmi_data *data, u8 val)
+{
+ struct bitland_mifs_input input = {
+ .operation = WMI_METHOD_SET,
+ .function = WMI_FN_SYSTEM_PER_MODE,
+ };
+ struct bitland_mifs_output output;
+ int ret;
+
+ input.payload[0] = val;
+
+ ret = bitland_mifs_wmi_call(data, &input, &output);
+ if (ret)
+ return ret;
+
+ if (output.operation != MIFS_STATUS_OK) {
+ dev_dbg(&data->wdev->dev,
+ "perf mode %#x rejected by firmware (status=%#x)\n",
+ val, output.operation);
+ return -EREMOTEIO;
+ }
+
+ return 0;
+}
+
+static int bitland_thin_profile_get(struct bitland_mifs_wmi_data *data,
+ enum platform_profile_option *profile)
+{
+ struct bitland_mifs_input input = {
+ .operation = WMI_METHOD_GET,
+ .function = WMI_FN_SYSTEM_PER_MODE,
+ };
+ struct bitland_mifs_output output;
+ int ret;
+
+ ret = bitland_mifs_wmi_call(data, &input, &output);
+ if (ret)
+ return ret;
+
+ switch (output.data[0]) {
+ case WMI_THIN_ECO:
+ case WMI_THIN_QUIET:
+ *profile = PLATFORM_PROFILE_LOW_POWER;
+ break;
+ case WMI_THIN_AUTO:
+ *profile = PLATFORM_PROFILE_BALANCED;
+ break;
+ case WMI_THIN_FULL_SPEED:
+ case WMI_THIN_TURBO:
+ *profile = PLATFORM_PROFILE_PERFORMANCE;
+ break;
+ default:
+ /*
+ * Unknown readback (e.g. Balance 0x01, not offered on
+ * TM24*): degrade to balanced rather than failing sysfs.
+ */
+ dev_dbg(&data->wdev->dev,
+ "unrecognized thin perf mode readback: %#x\n",
+ output.data[0]);
+ *profile = PLATFORM_PROFILE_BALANCED;
+ break;
+ }
+
+ return 0;
+}
+
+static int bitland_thin_profile_set(struct bitland_mifs_wmi_data *data,
+ enum platform_profile_option profile)
+{
+ switch (profile) {
+ case PLATFORM_PROFILE_LOW_POWER:
+ return bitland_thin_wmi_perf_set(data, WMI_THIN_ECO);
+ case PLATFORM_PROFILE_BALANCED:
+ return bitland_thin_wmi_perf_set(data, WMI_THIN_AUTO);
+ case PLATFORM_PROFILE_PERFORMANCE:
+ /*
+ * Full-speed is rejected by firmware on battery. There
+ * is no DC-jack on this model; honour the status byte
+ * and fall back to Turbo.
+ */
+ if (bitland_thin_wmi_perf_set(data, WMI_THIN_FULL_SPEED) == 0)
+ return 0;
+ return bitland_thin_wmi_perf_set(data, WMI_THIN_TURBO);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+/* --- Gaming-line (Tongfang/Redmi G) perf mode - unchanged behavior --- */
+
static int laptop_profile_get(struct device *dev,
enum platform_profile_option *profile)
{
@@ -197,6 +321,9 @@ static int laptop_profile_get(struct device *dev,
struct bitland_mifs_output result;
int ret;
+ if (data->thin_ultrabook)
+ return bitland_thin_profile_get(data, profile);
+
ret = bitland_mifs_wmi_call(data, &input, &result);
if (ret)
return ret;
@@ -256,6 +383,9 @@ static int laptop_profile_set(struct device *dev,
int ret;
u8 val;
+ if (data->thin_ultrabook)
+ return bitland_thin_profile_set(data, profile);
+
switch (profile) {
case PLATFORM_PROFILE_LOW_POWER:
val = WMI_PP_QUIET;
@@ -286,11 +416,20 @@ static int laptop_profile_set(struct device *dev,
static int platform_profile_probe(void *drvdata, unsigned long *choices)
{
+ struct bitland_mifs_wmi_data *data = drvdata;
+
set_bit(PLATFORM_PROFILE_LOW_POWER, choices);
set_bit(PLATFORM_PROFILE_BALANCED, choices);
- set_bit(PLATFORM_PROFILE_BALANCED_PERFORMANCE, choices);
set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
+ /*
+ * Thin-ultrabook line exposes exactly 3 firmware-backed levels
+ * (Eco/Auto/Full-speed-or-Turbo) - no separate
+ * balanced-performance step, unlike the gaming line's 4 modes.
+ */
+ if (!data->thin_ultrabook)
+ set_bit(PLATFORM_PROFILE_BALANCED_PERFORMANCE, choices);
+
return 0;
}
@@ -592,13 +731,35 @@ static const DEVICE_ATTR_RW(gpu_mode);
static const DEVICE_ATTR_RW(kb_mode);
static const DEVICE_ATTR_WO(fan_boost);
-static const struct attribute *const laptop_attrs[] = {
+static struct attribute *laptop_attrs[] = {
&dev_attr_gpu_mode.attr,
&dev_attr_kb_mode.attr,
&dev_attr_fan_boost.attr,
NULL,
};
-ATTRIBUTE_GROUPS(laptop);
+
+/* gpu_mode/kb_mode/fan_boost are unsupported on thin-ultrabook firmware. */
+static umode_t laptop_attrs_is_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct bitland_mifs_wmi_data *data = dev_get_drvdata(dev);
+
+ if (data->thin_ultrabook)
+ return 0;
+
+ return attr->mode;
+}
+
+static const struct attribute_group laptop_group = {
+ .attrs = laptop_attrs,
+ .is_visible = laptop_attrs_is_visible,
+};
+
+static const struct attribute_group *laptop_groups[] = {
+ &laptop_group,
+ NULL,
+};
static const struct key_entry bitland_mifs_wmi_keymap[] = {
{ KE_KEY, WMI_EVENT_OPEN_APP, { KEY_PROG1 } },
@@ -667,6 +828,7 @@ static int bitland_mifs_wmi_probe(struct wmi_device *wdev, const void *context)
return -ENOMEM;
drv_data->wdev = wdev;
+ drv_data->thin_ultrabook = dmi_check_system(bitland_mifs_thin_ultrabook_table) > 0;
ret = devm_mutex_init(&wdev->dev, &drv_data->lock);
if (ret)
@@ -693,12 +855,20 @@ static int bitland_mifs_wmi_probe(struct wmi_device *wdev, const void *context)
return input_register_device(drv_data->input_dev);
}
+ if (drv_data->thin_ultrabook)
+ dev_info(&wdev->dev, "using thin-ultrabook perf-mode values\n");
+
/* Register platform profile */
drv_data->pp_dev = devm_platform_profile_register(&wdev->dev, DRV_NAME, drv_data,
&laptop_profile_ops);
if (IS_ERR(drv_data->pp_dev))
return PTR_ERR(drv_data->pp_dev);
+ if (drv_data->thin_ultrabook) {
+ /* hwmon and keyboard LED WMI functions return 0xE0 here. */
+ return 0;
+ }
+
/* Register hwmon */
drv_data->hwmon_dev = devm_hwmon_device_register_with_info(&wdev->dev,
"bitland_mifs",
--
2.55.0