> My laptop has one RW data object, one RO data object, and one
> totally inaccessible data object. Check for the existence of the
> accessor methods and report in sysfs.
>
> The docs also permit WQxx getters for single-instance objects to
> take no parameters. Probe for that as well to avoid ACPICA warnings
> about mismatched signatures.
>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
> drivers/platform/x86/wmi.c | 94 ++++++++++++++++++++++++++++++++++++++++++++--
> include/linux/wmi.h | 6 +++
> 2 files changed, 96 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 5571ae7354a1..49be61207c4a 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -66,6 +66,8 @@ struct wmi_block {
> struct acpi_device *acpi_device;
> wmi_notify_handler handler;
> void *handler_data;
> +
> + bool read_takes_no_args; /* only defined if readable */
> };
>
>
> @@ -216,6 +218,25 @@ static bool find_guid(const char *guid_string, struct wmi_block **out)
> return false;
> }
>
> +static int get_subobj_info(acpi_handle handle, const char *pathname,
> + struct acpi_device_info *info)
> +{
> + acpi_handle subobj_handle;
> + acpi_status status;
> +
> + status = acpi_get_handle(handle, (char *)pathname, &subobj_handle);
> + if (status == AE_NOT_FOUND)
> + return -ENOENT;
> + else if (ACPI_FAILURE(status))
> + return -EIO;
> +
> + status = acpi_get_object_info(subobj_handle, &info);
acpi_get_object_info() allocates the returned buffer itself. The latter
should then subsequently be freed by the caller. One solution is to
change get_subobj_info() so that it takes a struct acpi_device_info **
as an argument, which should then be passed to acpi_get_object_info().
See also below.
> + if (ACPI_FAILURE(status))
> + return -EIO;
> +
> + return 0;
> +}
> +
> static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
> {
> struct guid_block *block = NULL;
> @@ -339,6 +360,9 @@ struct acpi_buffer *out)
> wq_params[0].type = ACPI_TYPE_INTEGER;
> wq_params[0].integer.value = instance;
>
> + if (instance == 0 && wblock->read_takes_no_args)
> + input.count = 0;
> +
> /*
> * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
> * enable collection.
> @@ -706,11 +730,37 @@ static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
> }
> static DEVICE_ATTR_RO(object_id);
>
> -static struct attribute *wmi_data_or_method_attrs[] = {
> +static ssize_t readable_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct wmi_device *wdev = dev_to_wdev(dev);
> +
> + return sprintf(buf, "%d\n", (int)wdev->readable);
> +}
> +static DEVICE_ATTR_RO(readable);
> +
> +static ssize_t writeable_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct wmi_device *wdev = dev_to_wdev(dev);
> +
> + return sprintf(buf, "%d\n", (int)wdev->writeable);
> +}
> +static DEVICE_ATTR_RO(writeable);
> +
> +static struct attribute *wmi_data_attrs[] = {
> &dev_attr_object_id.attr,
> + &dev_attr_readable.attr,
> + &dev_attr_writeable.attr,
> NULL,
> };
> -ATTRIBUTE_GROUPS(wmi_data_or_method);
> +ATTRIBUTE_GROUPS(wmi_data);
> +
> +static struct attribute *wmi_method_attrs[] = {
> + &dev_attr_object_id.attr,
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(wmi_method);
>
> static int wmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
> {
> @@ -809,13 +859,13 @@ static struct device_type wmi_type_event = {
>
> static struct device_type wmi_type_method = {
> .name = "method",
> - .groups = wmi_data_or_method_groups,
> + .groups = wmi_method_groups,
> .release = wmi_dev_release,
> };
>
> static struct device_type wmi_type_data = {
> .name = "data",
> - .groups = wmi_data_or_method_groups,
> + .groups = wmi_data_groups,
> .release = wmi_dev_release,
> };
>
> @@ -834,7 +884,43 @@ static int wmi_create_device(struct device *wmi_bus_dev,
> } else if (gblock->flags & ACPI_WMI_METHOD) {
> wblock->dev.dev.type = &wmi_type_method;
> } else {
> + struct acpi_device_info info;
struct acpi_device_info *info;
> + char method[5];
> + int result;
> +
> wblock->dev.dev.type = &wmi_type_data;
> +
> + strcpy(method, "WQ");
> + strncat(method, wblock->gblock.object_id, 2);
> + result = get_subobj_info(device->handle, method, &info);
> +
> + if (result == 0) {
> + wblock->dev.readable = true;
> +
> + /*
> + * The Microsoft documentation specifically states:
> + *
> + * Data blocks registered with only a single instance
> + * can ignore the parameter.
> + *
> + * ACPICA will get mad at us if we call the method
> + * with the wrong number of arguments, so check what
> + * our method expects. (On some Dell laptops, WQxx
> + * may not be a method at all.)
> + */
> + if (info.type != ACPI_TYPE_METHOD ||
> + info.param_count == 0)
> + wblock->read_takes_no_args = true;
kfree(info)
> + }
> +
> + strcpy(method, "WS");
> + strncat(method, wblock->gblock.object_id, 2);
> + result = get_subobj_info(device->handle, method, &info);
> +
> + if (result == 0) {
> + wblock->dev.writeable = true;
kfree(info)
--
Best regards,
Michał Kępień
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