On Thu, Jan 4, 2024 at 3:48 AM Kai-Heng Feng
<kai.heng.feng@xxxxxxxxxxxxx> wrote:
>
> The function of acpi_power_meter module on Dell system requires IPMI
> handler is installed and SMI is selected.
Does the firmware use _DEP to let the OS know about this dependency?
> So add a helper to let acpi_power_meter know when IPMI handler and SMI
> are ready.
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> ---
> v3:
> - New patch.
>
> drivers/acpi/acpi_ipmi.c | 17 ++++++++++++++++-
> include/acpi/acpi_bus.h | 5 +++++
> 2 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/acpi_ipmi.c b/drivers/acpi/acpi_ipmi.c
> index 0555f68c2dfd..54862cab7171 100644
> --- a/drivers/acpi/acpi_ipmi.c
> +++ b/drivers/acpi/acpi_ipmi.c
> @@ -23,6 +23,8 @@ MODULE_LICENSE("GPL");
> #define IPMI_TIMEOUT (5000)
> #define ACPI_IPMI_MAX_MSG_LENGTH 64
>
> +static struct completion smi_selected;
> +
> struct acpi_ipmi_device {
> /* the device list attached to driver_data.ipmi_devices */
> struct list_head head;
> @@ -463,8 +465,10 @@ static void ipmi_register_bmc(int iface, struct device *dev)
> if (temp->handle == handle)
> goto err_lock;
> }
> - if (!driver_data.selected_smi)
> + if (!driver_data.selected_smi) {
> driver_data.selected_smi = ipmi_device;
> + complete(&smi_selected);
> + }
> list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
> mutex_unlock(&driver_data.ipmi_lock);
>
> @@ -578,10 +582,21 @@ acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
> return status;
> }
>
> +int acpi_wait_for_acpi_ipmi(void)
> +{
> + long ret;
> +
> + ret = wait_for_completion_interruptible_timeout(&smi_selected, 2 * HZ);
> +
> + return ret > 0 ? 0 : -ETIMEDOUT;
What will happen if the IPMI driver is unloaded after this has returned 0?
> +}
> +EXPORT_SYMBOL_GPL(acpi_wait_for_acpi_ipmi);
> +
> static int __init acpi_ipmi_init(void)
> {
> int result;
> acpi_status status;
> + init_completion(&smi_selected);
>
> if (acpi_disabled)
> return 0;
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 1216d72c650f..afa6e4d4bf46 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -821,11 +821,16 @@ static inline void acpi_put_acpi_dev(struct acpi_device *adev)
> {
> acpi_dev_put(adev);
> }
> +
> +int acpi_wait_for_acpi_ipmi(void);
> +
> #else /* CONFIG_ACPI */
>
> static inline int register_acpi_bus_type(void *bus) { return 0; }
> static inline int unregister_acpi_bus_type(void *bus) { return 0; }
>
> +static inline int acpi_wait_for_acpi_ipmi(void) { return 0; }
> +
> #endif /* CONFIG_ACPI */
>
> #endif /*__ACPI_BUS_H__*/
> --
