On 06/06/2024 18:08, Rafael J. Wysocki wrote:
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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>
---
v1 -> v2:
* Instead of making the thermal debug code effectively ignore the invalid
initial cooling device state, simply don't register thermal debugfs for
a cooling device if its initial state returned by the driver's
.get_cur_state() is invalid (Daniel).
Laura, please test this one even though I don't see why it wouldn't work for
you if the v1 did.
---
drivers/thermal/thermal_core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -1001,7 +1001,7 @@ __thermal_cooling_device_register(struct
ret = cdev->ops->get_cur_state(cdev, ¤t_state);
if (ret)
- goto out_cdev_type;
+ current_state = ULONG_MAX;
Why not move the section ? So we end up below.
thermal_cooling_device_setup_sysfs(cdev);
@@ -1016,7 +1016,8 @@ __thermal_cooling_device_register(struct
return ERR_PTR(ret);
}
- thermal_debug_cdev_add(cdev, current_state);
+ if (current_state <= cdev->max_state)
+ thermal_debug_cdev_add(cdev, current_state);
ret = cdev->ops->get_cur_state(cdev, ¤t_state);
if (!ret)
thermal_debug_cdev_add(cdev, current_state);
Additionally a comment here to explain why get_cur_state can fail and
telling it is up to the driver to fix its routine?
/* Add 'this' new cdev to the global cdev list */
mutex_lock(&thermal_list_lock);
--
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