Re: [PATCH v3 2/2] hwmon: acpi_power_meter: convert to hwmon_device_register_with_info

[Guenter Roeck]

On 5/15/22 12:36, LABBE Corentin wrote:
> Le Wed, May 11, 2022 at 07:10:29PM -0700, Guenter Roeck a écrit :
> > Corentin,
> >
> > On 5/8/22 23:30, Corentin Labbe wrote:
> > > Booting lead to a hwmon_device_register() is deprecated. Please convert the driver to use hwmon_device_register_with_info().
> > > So let's convert the driver to use hwmon_device_register_with_info().
> > >
> > > Signed-off-by: Corentin Labbe <clabbe@xxxxxxxxxxxx>
> > > ---
> > [ ... ]
> >
> > > @@ -836,20 +740,20 @@ static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
> > >    		if (res)
> > >    			break;
> > >    
> > > -		remove_attrs(resource);
> > > +		remove_domain_devices(resource);
> > >    		setup_attrs(resource);
> >
> > Zhang Rui found an interesting problem with this code:
> > It needs a call to sysfs_update_groups(hwmon_dev->groups)
> > to update sysfs attribute visibility, probably between
> > remove_domain_devices() and setup_attrs().
> >
> > >    		break;
> > >    	case METER_NOTIFY_TRIP:
> > > -		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
> > > +		hwmon_notify_event(&device->dev, hwmon_power, hwmon_power_average, 0);
> >
> > ... which makes realize: The notification device should be the hwmon device.
> > That would be resource->hwmon_dev, not the acpi device.
>
> Hello
>
> Since my hardware lacks capabilities testing this, I have emulated it on qemu:
> https://github.com/montjoie/qemu/commit/320f2ddacb954ab308ef699f66fca6313f75bc2b
>
> I have added a custom ACPI _DBX method for triggering some ACPI state change. (like config change, like enabling CAP).
>
> For testing config change I have tried lot of way:
>                  res = read_capabilities(resource);
> @@ -742,18 +758,22 @@ static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
>   
>                  remove_domain_devices(resource);
>                  setup_attrs(resource);
> +               res = sysfs_update_groups(&resource->hwmon_dev->kobj, acpi_power_groups);
> +               res = sysfs_update_groups(&resource->acpi_dev->dev.kobj, acpi_power_groups);
> +               res = hwmon_notify_event(resource->hwmon_dev, hwmon_power, hwmon_power_cap, 0);
> +               res = hwmon_notify_event(resource->hwmon_dev, hwmon_power, hwmon_power_average, 0);

Did you add a debug log here ?

acpi_power_groups would be the wrong parameter for sysfs_update_groups().
It would have to be resource->hwmon_dev->groups.

Guenter

>                  break;
>          case METER_NOTIFY_TRIP:
> -               hwmon_notify_event(&device->dev, hwmon_power, hwmon_power_average, 0);
> +               res = hwmon_notify_event(resource->hwmon_dev, hwmon_power, hwmon_power_average, 0);
>                  break;
>          case METER_NOTIFY_CAP:
> -               hwmon_notify_event(&device->dev, hwmon_power, hwmon_power_cap, 0);
> +               res = hwmon_notify_event(resource->hwmon_dev, hwmon_power, hwmon_power_cap, 0);
>                  break;
>          case METER_NOTIFY_INTERVAL:
> -               hwmon_notify_event(&device->dev, hwmon_power, hwmon_power_average_interval, 0);
> +               res = hwmon_notify_event(resource->hwmon_dev, hwmon_power, hwmon_power_average_interval, 0);
>                  break;
>          case METER_NOTIFY_CAPPING:
> -               hwmon_notify_event(&device->dev, hwmon_power, hwmon_power_alarm, 0);
> +               res = hwmon_notify_event(resource->hwmon_dev, hwmon_power, hwmon_power_alarm, 0);
>                  dev_info(&device->dev, "Capping in progress.\n");
>                  break;
>          default:
>
> But nothing force visibility to be rerun.
>
> Any idea on how to force visibility to be re-run ?