[PATCH 4/5] alienware-wmi: create_thermal_profile no longer brute-forces IDs

[Kurt Borja <kuurtb@gmail.com>]

WMAX_METHOD_THERMAL_INFORMATION has a *system description* operation
that outputs a buffer with the following structure:

out[0] -> Number of fans
out[1] -> Number of sensors
out[2] -> 0x00
out[3] -> Number of thermal modes

This is now used by create_thermal_profile to retrieve available thermal
codes instead of brute-forcing every ID.

Tested on an Alienware x15 R1. Verified by checking ACPI tables of
supported models.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 drivers/platform/x86/dell/alienware-wmi.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/dell/alienware-wmi.c b/drivers/platform/x86/dell/alienware-wmi.c
index 36d182f217e2..77465ed9b449 100644
--- a/drivers/platform/x86/dell/alienware-wmi.c
+++ b/drivers/platform/x86/dell/alienware-wmi.c
@@ -68,6 +68,7 @@ enum WMAX_CONTROL_STATES {
 };
 
 enum WMAX_THERMAL_INFORMATION_OPERATIONS {
+	WMAX_OPERATION_SYS_DESCRIPTION		= 0x02,
 	WMAX_OPERATION_LIST_IDS			= 0x03,
 	WMAX_OPERATION_CURRENT_PROFILE		= 0x0B,
 };
@@ -1110,13 +1111,22 @@ static int thermal_profile_set(struct platform_profile_handler *pprof,
 static int create_thermal_profile(void)
 {
 	u32 out_data;
+	u8 sys_desc[4];
+	u32 first_mode;
 	enum wmax_thermal_mode mode;
 	enum platform_profile_option profile;
 	int ret;
 
-	for (u8 i = 0x2; i <= 0xD; i++) {
+	ret = wmax_thermal_information(WMAX_OPERATION_SYS_DESCRIPTION,
+				       0, (u32 *) &sys_desc);
+	if (ret < 0)
+		return ret;
+
+	first_mode = sys_desc[0] + sys_desc[1];
+
+	for (u32 i = 0; i < sys_desc[3]; i++) {
 		ret = wmax_thermal_information(WMAX_OPERATION_LIST_IDS,
-					       i, &out_data);
+					       i + first_mode, &out_data);
 
 		if (ret == -EIO)
 			return ret;
-- 
2.47.0