> -----Original Message-----
> From: Daniel Dadap <ddadap@xxxxxxxxxx>
> Sent: Friday, July 31, 2020 3:22 PM
> To: platform-driver-x86@xxxxxxxxxxxxxxx; Limonciello, Mario;
> pobrn@xxxxxxxxxxxxxx
> Cc: andy@xxxxxxxxxxxxx; dvhart@xxxxxxxxxxxxx; aplattner@xxxxxxxxxx; Daniel
> Dadap
> Subject: [PATCH v2 2/2] platform/x86: wmi: fail wmi_driver_register when no
> GUID is found
>
>
> [EXTERNAL EMAIL]
>
> If a driver registers with WMI, and none of the GUIDs in its ID table
> is present on the system, then that driver will not be probed and
> automatically loaded. However, it is still possible to load such a
> driver explicitly on a system which doesn't include the relevant
> hardware.
>
> Update wmi_driver_register to test for the presence of at least one
> GUID from the driver's ID table at driver registration time, and
> fail registration if none are found.
>
> Signed-off-by: Daniel Dadap <ddadap@xxxxxxxxxx>
> ---
> drivers/platform/x86/wmi.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 941739db7199..19aa23d1cf8e 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -130,6 +130,21 @@ static bool find_guid(const char *guid_string, struct
> wmi_block **out)
> return false;
> }
>
> +static bool find_driver_guid(const struct wmi_driver *wdriver)
> +{
> + const struct wmi_device_id *id;
> +
> + if (wdriver == NULL)
> + return false;
> +
> + for (id = wdriver->id_table; *id->guid_string; id++) {
> + if (find_guid(id->guid_string, NULL))
> + return true;
> + }
> +
> + return false;
> +}
> +
As a point of preference, why not in this function return -ENODEV directly
rather than it be boolean and map all errors to -ENODEV?
> static const void *find_guid_context(struct wmi_block *wblock,
> struct wmi_driver *wdriver)
> {
> @@ -1419,6 +1434,9 @@ static int acpi_wmi_probe(struct platform_device
> *device)
> int __must_check __wmi_driver_register(struct wmi_driver *driver,
> struct module *owner)
> {
> + if (!find_driver_guid(driver))
> + return -ENODEV;
> +
Then the logic here can be something like:
ret = find_driver_guid(driver);
if (ret)
return ret;
> driver->driver.owner = owner;
> driver->driver.bus = &wmi_bus_type;
>
> --
> 2.18.4
