From: Rafael J. Wysocki <[email protected]>
Subject: [PATCH v3] thermal: core: Do not fail cdev registration because of invalid initial state
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/[email protected]
Reported-by: Laura Nao <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
v2 -> v3:
* Add a comment to explain the initial state of a cooling device (Daniel).
No functional changes.
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 | 13 +++++++++++--
1 file changed, 11 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
@@ -999,9 +999,17 @@ __thermal_cooling_device_register(struct
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);
@@ -1016,7 +1024,8 @@ __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);
/* Add 'this' new cdev to the global cdev list */
mutex_lock(&thermal_list_lock);
On 06/06/2024 20:14, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
> Subject: [PATCH v3] thermal: core: Do not fail cdev registration because of invalid initial state
>
> 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/[email protected]
> Reported-by: Laura Nao <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> ---
Acked-by: Daniel Lezcano <[email protected]>
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On 6/6/24 20:14, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
> Subject: [PATCH v3] thermal: core: Do not fail cdev registration
> because of invalid initial state
>
> 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/[email protected]
> Reported-by: Laura Nao <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> ---
Tested-by: Laura Nao <[email protected]>
Thanks,
Laura