This is a note to let you know that I've just added the patch titled hwmon: (mlxreg-fan) Return zero speed for broken fan to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hwmon-mlxreg-fan-return-zero-speed-for-broken-fan.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 889654de46c3c400b6d521bb6ac832dc68f538c8 Author: Vadim Pasternak <vadimp@xxxxxxxxxx> Date: Sun Feb 12 16:57:30 2023 +0200 hwmon: (mlxreg-fan) Return zero speed for broken fan [ Upstream commit a1ffd3c46267ee5c807acd780e15df9bb692223f ] Currently for broken fan driver returns value calculated based on error code (0xFF) in related fan speed register. Thus, for such fan user gets fan{n}_fault to 1 and fan{n}_input with misleading value. Add check for fan fault prior return speed value and return zero if fault is detected. Fixes: 65afb4c8e7e4 ("hwmon: (mlxreg-fan) Add support for Mellanox FAN driver") Signed-off-by: Vadim Pasternak <vadimp@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230212145730.24247-1-vadimp@xxxxxxxxxx Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/hwmon/mlxreg-fan.c b/drivers/hwmon/mlxreg-fan.c index 89fe7b9fe26be..6ecc45c06849c 100644 --- a/drivers/hwmon/mlxreg-fan.c +++ b/drivers/hwmon/mlxreg-fan.c @@ -151,6 +151,12 @@ mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, if (err) return err; + if (MLXREG_FAN_GET_FAULT(regval, tacho->mask)) { + /* FAN is broken - return zero for FAN speed. */ + *val = 0; + return 0; + } + *val = MLXREG_FAN_GET_RPM(regval, fan->divider, fan->samples); break;