[PATCH v1 2/2] platform/x86: asus-armoury: add dGPU disable fallback DEVID for ProArt H7606 series

[Denis Benato <denis.benato@linux.dev>]

Newer ASUS ProArt laptops (e.g. H7606 series) implement dGPU power
control on WMI DEVID 0x00090120 instead of the usual 0x00090020.
The default DEVID returns 0xFFFFFFE2 on these models, so the
dgpu_disable firmware attribute is never created and the dGPU cannot
be re-enabled from Linux at all.

Add a fallback probe for device ID 0x00090120 following the same
approach as the gpu_mux_dev_id probe.

Details for 0x00090120 (confirmed on H7606W using direct WMNB calls
and inspecting the DSDT DEVS handler):
  - Reading DSTS returns 0x00010001 when the dGPU is off (CUMA=1),
	or 0x00010000 when it's on.
  - Writing DEVS: 0 enables the dGPU (calls PG00._ON() + Notifies
	PEGP, Device Check), and 1 disables or ejects it.

This behavior matches the dgpu_disable attribute (1 = disabled).

Signed-off-by: Denis Benato <denis.benato@linux.dev>
---
 drivers/platform/x86/asus-armoury.c        | 2 ++
 include/linux/platform_data/x86/asus-wmi.h | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/drivers/platform/x86/asus-armoury.c b/drivers/platform/x86/asus-armoury.c
index 8639902f084d..3cbee734180a 100644
--- a/drivers/platform/x86/asus-armoury.c
+++ b/drivers/platform/x86/asus-armoury.c
@@ -977,6 +977,8 @@ static int asus_fw_attr_add(void)
 	asus_armoury.dgpu_disable_dev_id = 0;
 	if (armoury_has_devstate(ASUS_WMI_DEVID_DGPU))
 		asus_armoury.dgpu_disable_dev_id = ASUS_WMI_DEVID_DGPU;
+	else if (armoury_has_devstate(ASUS_WMI_DEVID_GPU_MODE))
+		asus_armoury.dgpu_disable_dev_id = ASUS_WMI_DEVID_GPU_MODE;
 
 	err = sysfs_create_group(&asus_armoury.fw_attr_kset->kobj,
 				 &mini_led_mode_attr_group);
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 289be6ac7335..2cd2776ad6fb 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -138,6 +138,9 @@
 /* dgpu on/off */
 #define ASUS_WMI_DEVID_DGPU		0x00090020
 
+/* dgpu on/off - alternative to ASUS_WMI_DEVID_DGPU */
+#define ASUS_WMI_DEVID_GPU_MODE		0x00090120
+
 #define ASUS_WMI_DEVID_APU_MEM		0x000600C1
 
 #define ASUS_WMI_DEVID_DGPU_POWER_STATE	0x00120097
-- 
2.47.3