platform/x86: asus-wmi: Support the hardware GPU MUX on some laptops

Support the hardware GPU MUX switch available on some models. This
switch can toggle the MUX between:

- 0, Dedicated mode
- 1, Optimus mode

Optimus mode is the regular iGPU + dGPU available, while dedicated
mode switches the system to have only the dGPU available.

Signed-off-by: Luke D. Jones <luke@ljones.dev>
Link: https://lore.kernel.org/r/20220813092624.6228-1-luke@ljones.dev
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/Documentation/ABI/testing/sysfs-platform-asus-wmi b/Documentation/ABI/testing/sysfs-platform-asus-wmi
index 4d63824..a77a004 100644 (file)
--- a/Documentation/ABI/testing/sysfs-platform-asus-wmi
+++ b/Documentation/ABI/testing/sysfs-platform-asus-wmi
@@ -58,6 +58,18 @@ Description:
                        * 1 - overboost,
                        * 2 - silent
 
+What:          /sys/devices/platform/<platform>/gpu_mux_mode
+Date:          Aug 2022
+KernelVersion: 6.1
+Contact:       "Luke Jones" <luke@ljones.dev>
+Description:
+               Switch the GPU hardware MUX mode. Laptops with this feature can
+               can be toggled to boot with only the dGPU (discrete mode) or in
+               standard Optimus/Hybrid mode. On switch a reboot is required:
+
+                       * 0 - Discrete GPU,
+                       * 1 - Optimus/Hybrid,
+
 What:          /sys/devices/platform/<platform>/dgpu_disable
 Date:          Aug 2022
 KernelVersion: 5.17

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index d72491f..46d0dd9 100644 (file)
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -231,6 +231,7 @@ struct asus_wmi {
 
        bool egpu_enable_available;
        bool dgpu_disable_available;
+       bool gpu_mux_mode_available;
 
        bool throttle_thermal_policy_available;
        u8 throttle_thermal_policy_mode;
@@ -657,6 +658,52 @@ static ssize_t egpu_enable_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(egpu_enable);
 
+/* gpu mux switch *************************************************************/
+static ssize_t gpu_mux_mode_show(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+       struct asus_wmi *asus = dev_get_drvdata(dev);
+       int result;
+
+       result = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_GPU_MUX);
+       if (result < 0)
+               return result;
+
+       return sysfs_emit(buf, "%d\n", result);
+}
+
+static ssize_t gpu_mux_mode_store(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf, size_t count)
+{
+       struct asus_wmi *asus = dev_get_drvdata(dev);
+       int result, err;
+       u32 optimus;
+
+       err = kstrtou32(buf, 10, &optimus);
+       if (err)
+               return err;
+
+       if (optimus > 1)
+               return -EINVAL;
+
+       err = asus_wmi_set_devstate(ASUS_WMI_DEVID_GPU_MUX, optimus, &result);
+       if (err) {
+               dev_err(dev, "Failed to set GPU MUX mode: %d\n", err);
+               return err;
+       }
+       /* !1 is considered a fail by ASUS */
+       if (result != 1) {
+               dev_warn(dev, "Failed to set GPU MUX mode (result): 0x%x\n", result);
+               return -EIO;
+       }
+
+       sysfs_notify(&asus->platform_device->dev.kobj, NULL, "gpu_mux_mode");
+
+       return count;
+}
+static DEVICE_ATTR_RW(gpu_mux_mode);
+
 /* Battery ********************************************************************/
 
 /* The battery maximum charging percentage */
@@ -3172,6 +3219,7 @@ static struct attribute *platform_attributes[] = {
        &dev_attr_touchpad.attr,
        &dev_attr_egpu_enable.attr,
        &dev_attr_dgpu_disable.attr,
+       &dev_attr_gpu_mux_mode.attr,
        &dev_attr_lid_resume.attr,
        &dev_attr_als_enable.attr,
        &dev_attr_fan_boost_mode.attr,
@@ -3202,6 +3250,8 @@ static umode_t asus_sysfs_is_visible(struct kobject *kobj,
                ok = asus->egpu_enable_available;
        else if (attr == &dev_attr_dgpu_disable.attr)
                ok = asus->dgpu_disable_available;
+       else if (attr == &dev_attr_gpu_mux_mode.attr)
+               ok = asus->gpu_mux_mode_available;
        else if (attr == &dev_attr_fan_boost_mode.attr)
                ok = asus->fan_boost_mode_available;
        else if (attr == &dev_attr_throttle_thermal_policy.attr)
@@ -3465,6 +3515,7 @@ static int asus_wmi_add(struct platform_device *pdev)
 
        asus->egpu_enable_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_EGPU);
        asus->dgpu_disable_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_DGPU);
+       asus->gpu_mux_mode_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_GPU_MUX);
        asus->panel_overdrive_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_PANEL_OD);
 
        err = fan_boost_mode_check_present(asus);

diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 98f2b2f..70d2347 100644 (file)
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -99,6 +99,9 @@
 /* dgpu on/off */
 #define ASUS_WMI_DEVID_DGPU            0x00090020
 
+/* gpu mux switch, 0 = dGPU, 1 = Optimus */
+#define ASUS_WMI_DEVID_GPU_MUX         0x00090016
+
 /* DSTS masks */
 #define ASUS_WMI_DSTS_STATUS_BIT       0x00000001
 #define ASUS_WMI_DSTS_UNKNOWN_BIT      0x00000002