6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
[ Upstream commit 1af89dedc8a58006d8e385b1e0d2cd24df8a3b69 ]
It is reported that commit 31a0fa0019b0 ("thermal/debugfs: Pass cooling
device state to thermal_debug_cdev_add()") causes the ACPI fan driver
to fail probing on some systems which turns out to be due to the _FST
control method returning an invalid value until _FSL is first evaluated
for the given fan. If this happens, the .get_cur_state() cooling device
callback returns an error and __thermal_cooling_device_register() fails
as uses that callback after commit 31a0fa0019b0.
Arguably, _FST should not return an invalid value even if it is
evaluated before _FSL, so this may be regarded as a platform firmware
issue, but at the same time it is not a good enough reason for failing
the cooling device registration where the initial cooling device state
is only needed to initialize a thermal debug facility.
Accordingly, modify __thermal_cooling_device_register() to avoid
calling thermal_debug_cdev_add() instead of returning an error if the
initial .get_cur_state() callback invocation fails.
Fixes: 31a0fa0019b0 ("thermal/debugfs: Pass cooling device state to thermal_debug_cdev_add()")
Closes: https://lore.kernel.org/linux-acpi/20240530153727.843378-1-laura.nao@xxxxxxxxxxxxx
Reported-by: Laura Nao <laura.nao@xxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Tested-by: Laura Nao <laura.nao@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/thermal/thermal_core.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 38b7d02384d7c..258482036f1e9 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -936,9 +936,17 @@ __thermal_cooling_device_register(struct device_node *np,
if (ret)
goto out_cdev_type;
+ /*
+ * The cooling device's current state is only needed for debug
+ * initialization below, so a failure to get it does not cause
+ * the entire cooling device initialization to fail. However,
+ * the debug will not work for the device if its initial state
+ * cannot be determined and drivers are responsible for ensuring
+ * that this will not happen.
+ */
ret = cdev->ops->get_cur_state(cdev, ¤t_state);
if (ret)
- goto out_cdev_type;
+ current_state = ULONG_MAX;
thermal_cooling_device_setup_sysfs(cdev);
@@ -953,7 +961,8 @@ __thermal_cooling_device_register(struct device_node *np,
return ERR_PTR(ret);
}
- thermal_debug_cdev_add(cdev, current_state);
+ if (current_state <= cdev->max_state)
+ thermal_debug_cdev_add(cdev, current_state);
/* Add 'this' new cdev to the global cdev list */
mutex_lock(&thermal_list_lock);
--
2.43.0
