[PATCH] platform/x86: thinkpad_acpi: Correct dual fan probe

[Mark Pearson <markpearson@lenovo.com>]

There was an issue with the dual fan probe whereby the probe was
failing as it assuming that second_fan support was not available.

Corrected the logic so the probe works correctly. Cleaned up so
quirks only used if 2nd fan not detected.

Tested on X1 Carbon 10 (2 fans), X1 Carbon 9 (2 fans) and T490 (1 fan)

Signed-off-by: Mark Pearson <markpearson@lenovo.com>
---
 drivers/platform/x86/thinkpad_acpi.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index f385450af864..5eea6651a312 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -8862,24 +8862,27 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 			fan_status_access_mode = TPACPI_FAN_RD_TPEC;
 			if (quirks & TPACPI_FAN_Q1)
 				fan_quirk1_setup();
-			if (quirks & TPACPI_FAN_2FAN) {
-				tp_features.second_fan = 1;
-				pr_info("secondary fan support enabled\n");
-			}
-			if (quirks & TPACPI_FAN_2CTL) {
-				tp_features.second_fan = 1;
-				tp_features.second_fan_ctl = 1;
-				pr_info("secondary fan control enabled\n");
-			}
 			/* Try and probe the 2nd fan */
+			tp_features.second_fan = 1; /* needed for get_speed to work */
 			res = fan2_get_speed(&speed);
 			if (res >= 0) {
 				/* It responded - so let's assume it's there */
 				tp_features.second_fan = 1;
 				tp_features.second_fan_ctl = 1;
 				pr_info("secondary fan control detected & enabled\n");
+			} else {
+				/* Fan not auto-detected */
+				tp_features.second_fan = 0;
+				if (quirks & TPACPI_FAN_2FAN) {
+					tp_features.second_fan = 1;
+					pr_info("secondary fan support enabled\n");
+				}
+				if (quirks & TPACPI_FAN_2CTL) {
+					tp_features.second_fan = 1;
+					tp_features.second_fan_ctl = 1;
+					pr_info("secondary fan control enabled\n");
+				}
 			}
-
 		} else {
 			pr_err("ThinkPad ACPI EC access misbehaving, fan status and control unavailable\n");
 			return -ENODEV;
-- 
2.35.1