Re: [PATCH v3 1/3] platform/x86: dell-privacy: Add support for Dell hardware privacy

[Pierre-Louis Bossart]

> > > +static const struct acpi_device_id privacy_acpi_device_ids[] = {
> > > +    {"PNP0C09", 0},
> > > +    { },
> > > +};
> > > +MODULE_DEVICE_TABLE(acpi, privacy_acpi_device_ids);
> > > +
> > > +static struct platform_driver dell_privacy_platform_drv = {
> > > +    .driver = {
> > > +        .name = PRIVACY_PLATFORM_NAME,
> > > +        .acpi_match_table = ACPI_PTR(privacy_acpi_device_ids),
> > > +    },
> >
> > no .probe?
> Originally i added the probe here, but it cause the driver  .probe 
> called twice. after i use platform_driver_probe to register the driver 
> loading process, the duplicated probe issue resolved.
>
> I
> > > +    .remove = dell_privacy_acpi_remove,
> > > +};
> > > +
> > > +int __init dell_privacy_acpi_init(void)
> > > +{
> > > +    int err;
> > > +    struct platform_device *pdev;
> > > +    int privacy_capable = wmi_has_guid(DELL_PRIVACY_GUID);
> > > +
> > > +    if (!wmi_has_guid(DELL_PRIVACY_GUID))
> > > +        return -ENODEV;
> > > +
> > > +    privacy_acpi = kzalloc(sizeof(*privacy_acpi), GFP_KERNEL);
> > > +    if (!privacy_acpi)
> > > +        return -ENOMEM;
> > > +
> > > +    pdev = platform_device_register_simple(
> > > +            PRIVACY_PLATFORM_NAME, PLATFORM_DEVID_NONE, NULL, 0);
> > > +    if (IS_ERR(pdev)) {
> > > +        err = PTR_ERR(pdev);
> > > +        goto pdev_err;
> > > +    }
> > > +    err = platform_driver_probe(&dell_privacy_platform_drv,
> > > +            dell_privacy_acpi_probe);
> > > +    if (err)
> > > +        goto pdrv_err;
> >
> > why is the probe done here? Put differently, what prevents you from 
> > using a 'normal' platform driver, and do the leds_setup in the .probe()?
> At first ,I used the normal platform driver framework, however tt cause 
> the driver  .probe called twice. after i use platform_driver_probe to 
> register the driver loading process, the duplicated probe issue resolved.

This sounds very odd...

this looks like a conflict with the ACPI subsystem finding a device and 
probing the driver that's associated with the PNP0C09 HID, and then this 
module __init  creating a device manually which leads to a second probe

Neither the platform_device_register_simple() nor 
platform_driver_probe() seem necessary?