From: Jelle van der Waa <jvanderwaa@xxxxxxxxxx> [ Upstream commit a10d50983f7befe85acf95ea7dbf6ba9187c2d70 ] thinkpad_acpi was reporting 2 fans on a ThinkPad T14s gen 1, even though the laptop has only 1 fan. The second, not present fan always reads 65535 (-1 in 16 bit signed), ignore fans which report 65535 to avoid reporting the non present fan. Signed-off-by: Jelle van der Waa <jvanderwaa@xxxxxxxxxx> Link: https://lore.kernel.org/r/20221019194751.5392-1-jvanderwaa@xxxxxxxxxx Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/platform/x86/thinkpad_acpi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c index 2dbb9fc011a7..353507d18e11 100644 --- a/drivers/platform/x86/thinkpad_acpi.c +++ b/drivers/platform/x86/thinkpad_acpi.c @@ -263,6 +263,8 @@ enum tpacpi_hkey_event_t { #define TPACPI_DBG_BRGHT 0x0020 #define TPACPI_DBG_MIXER 0x0040 +#define FAN_NOT_PRESENT 65535 + #define strlencmp(a, b) (strncmp((a), (b), strlen(b))) @@ -8876,7 +8878,7 @@ static int __init fan_init(struct ibm_init_struct *iibm) /* 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) { + if (res >= 0 && speed != FAN_NOT_PRESENT) { /* It responded - so let's assume it's there */ tp_features.second_fan = 1; tp_features.second_fan_ctl = 1; -- 2.35.1
