Am 27.04.23 um 11:43 schrieb Hans de Goede:
Hi Armin, Thank you for your work on this. On 4/26/23 23:28, Armin Wolf wrote:Currently, the WMI driver core knows how many instances of a given WMI object exist, but WMI drivers cannot access this information. At the same time, some current and upcoming WMI drivers want to have access to this information. Add wmi_instance_count() and wmidev_instance_count() to allow WMI drivers to get the number of WMI object instances. Signed-off-by: Armin Wolf <W_Armin@xxxxxx> --- drivers/platform/x86/wmi.c | 40 ++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 2 ++ include/linux/wmi.h | 2 ++ 3 files changed, 44 insertions(+) diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index c226dd4163a1..7c1a904dec5f 100644 --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -263,6 +263,46 @@ int set_required_buffer_size(struct wmi_device *wdev, u64 length) } EXPORT_SYMBOL_GPL(set_required_buffer_size); +/** + * wmi_instance_count - Get number of WMI object instances + * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba + * @instance_count: variable to hold the instance count + * + * Get the number of WMI object instances. + * + * Returns: acpi_status signaling success or error. + */ +acpi_status wmi_instance_count(const char *guid_string, u8 *instance_count) +{ + struct wmi_block *wblock; + acpi_status status; + + status = find_guid(guid_string, &wblock); + if (ACPI_FAILURE(status)) + return status; + + *instance_count = wmidev_instance_count(&wblock->dev); + + return AE_OK; +} +EXPORT_SYMBOL_GPL(wmi_instance_count);I would prefer this to have a normal kernel function prototype which returns -errno rather then returning an acpi_status. E.g. : /** * wmi_instance_count - Get number of WMI object instances * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba * * Get the number of WMI object instances. * * Returns: The number of WMI object instances, 0 if the GUID is not found. */ int wmi_instance_count(const char *guid_string) { struct wmi_block *wblock; acpi_status status; status = find_guid(guid_string, &wblock); if (ACPI_FAILURE(status)) return 0; return wmidev_instance_count(&wblock->dev); } EXPORT_SYMBOL_GPL(wmi_instance_count); This will also allow this to completely replace the get_instance_count() function in dell-wmi-sysman. Note I have just gone with always returning 0 here on error. I guess you could look at the status and return 0 for not-found and -errno for other errors but I don't think any callers will care for the difference, so just always returning 0 seems easier for callers to deal with. As always this is just a suggestion, let me know if you think this is a bad idea. Regards, Hans
I like this idea. Returning a negative errno on error would allow drivers to distinguish between "WMI object not found" and "zero instances found", which might be useful for some drivers. Maybe a function for converting ACPI errors to POSIX errors already exists, otherwise i will just write one myself. Armin Wolf
+ +/** + * wmidev_instance_count - Get number of WMI object instances + * @wdev: A wmi bus device from a driver + * + * Get the number of WMI object instances. + * + * Returns: Number of WMI object instances. + */ +u8 wmidev_instance_count(struct wmi_device *wdev) +{ + struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev); + + return wblock->gblock.instance_count; +} +EXPORT_SYMBOL_GPL(wmidev_instance_count); + /** * wmi_evaluate_method - Evaluate a WMI method (deprecated) * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba diff --git a/include/linux/acpi.h b/include/linux/acpi.h index efff750f326d..ab2a4b23e7a3 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -412,6 +412,8 @@ extern bool acpi_is_pnp_device(struct acpi_device *); typedef void (*wmi_notify_handler) (u32 value, void *context); +acpi_status wmi_instance_count(const char *guid, u8 *instance_count); + extern acpi_status wmi_evaluate_method(const char *guid, u8 instance, u32 method_id, const struct acpi_buffer *in, diff --git a/include/linux/wmi.h b/include/linux/wmi.h index c1a3bd4e4838..763bd382cf2d 100644 --- a/include/linux/wmi.h +++ b/include/linux/wmi.h @@ -35,6 +35,8 @@ extern acpi_status wmidev_evaluate_method(struct wmi_device *wdev, extern union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance); +u8 wmidev_instance_count(struct wmi_device *wdev); + extern int set_required_buffer_size(struct wmi_device *wdev, u64 length); /** -- 2.30.2
