On Sun, 8 Oct 2023, Armin Wolf wrote:
> Many aggregate WMI drivers do not use -EPROBE_DEFER when they
> cannot find a WMI device during probe, instead they require
> all WMI devices associated with an platform device to become
> available at once. This is currently achieved by adding those
> WMI devices to the wmi_block_list before they are registered,
> which is then used by the deprecated GUID-based functions to
> search for WMI devices.
> Replace this approach with a device link which defers probing
To make these more readable, you should break the paragraphs with an empty
line, not just using a newline.
--
i.
> of the WMI device until the associated platform device has finished
> probing (and has registered all WMI devices). New aggregate WMI
> drivers should not rely on this behaviour.
> Signed-off-by: Armin Wolf <W_Armin@xxxxxx>
> ---
> drivers/platform/x86/wmi.c | 39 +++++++++++++++++++++++++-------------
> 1 file changed, 26 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index a78ddd83cda0..1dbef16acdeb 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1221,6 +1221,26 @@ static int wmi_create_device(struct device *wmi_bus_dev,
> return 0;
> }
>
> +static int wmi_add_device(struct platform_device *pdev, struct wmi_device *wdev)
> +{
> + struct device_link *link;
> +
> + /*
> + * Many aggregate WMI drivers do not use -EPROBE_DEFER when they
> + * are unable to find a WMI device during probe, instead they require
> + * all WMI devices associated with an platform device to become available
> + * at once. This device link thus prevents WMI drivers from probing until
> + * the associated platform device has finished probing (and has registered
> + * all discovered WMI devices).
> + */
> +
> + link = device_link_add(&wdev->dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
> + if (!link)
> + return -EINVAL;
> +
> + return device_add(&wdev->dev);
> +}
> +
> static void wmi_free_devices(struct acpi_device *device)
> {
> struct wmi_block *wblock, *next;
> @@ -1263,11 +1283,12 @@ static bool guid_already_parsed_for_legacy(struct acpi_device *device, const gui
> /*
> * Parse the _WDG method for the GUID data blocks
> */
> -static int parse_wdg(struct device *wmi_bus_dev, struct acpi_device *device)
> +static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
> {
> + struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
> struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
> const struct guid_block *gblock;
> - struct wmi_block *wblock, *next;
> + struct wmi_block *wblock;
> union acpi_object *obj;
> acpi_status status;
> int retval = 0;
> @@ -1317,22 +1338,14 @@ static int parse_wdg(struct device *wmi_bus_dev, struct acpi_device *device)
> wblock->handler = wmi_notify_debug;
> wmi_method_enable(wblock, true);
> }
> - }
>
> - /*
> - * Now that all of the devices are created, add them to the
> - * device tree and probe subdrivers.
> - */
> - list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
> - if (wblock->acpi_device != device)
> - continue;
> -
> - retval = device_add(&wblock->dev.dev);
> + retval = wmi_add_device(pdev, &wblock->dev);
> if (retval) {
> dev_err(wmi_bus_dev, "failed to register %pUL\n",
> &wblock->gblock.guid);
> if (debug_event)
> wmi_method_enable(wblock, false);
> +
> list_del(&wblock->list);
> put_device(&wblock->dev.dev);
> }
> @@ -1487,7 +1500,7 @@ static int acpi_wmi_probe(struct platform_device *device)
> }
> dev_set_drvdata(&device->dev, wmi_bus_dev);
>
> - error = parse_wdg(wmi_bus_dev, acpi_device);
> + error = parse_wdg(wmi_bus_dev, device);
> if (error) {
> pr_err("Failed to parse WDG method\n");
> goto err_remove_busdev;
> --
> 2.39.2
>
