linux-kernel - Re: [PATCH v2] platform/x86: wmi: Use ACPI device name in netlink event

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Date: Mon, 22 Jan 2024 12:29:43 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Armin Wolf <W_Armin@....de>, ilpo.jarvinen@...ux.intel.com,
 Andy Shevchenko <andy@...nel.org>
Cc: platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] platform/x86: wmi: Use ACPI device name in netlink
 event

Hi Armin,

On 1/21/24 21:08, Armin Wolf wrote:
> The device name inside the ACPI netlink event is limited to
> 15 characters, so the WMI device name will get truncated.
> 
> This can be observed with kacpimon when receiving an event
> from WMI device "9DBB5994-A997-11DA-B012-B622A1EF5492":
> 
> 	netlink:  9DBB5994-A997- 000000d0 00000000
> 
> Fix this by using the shorter device name from the ACPI
> bus device instead. This still allows users to uniquely
> identify the WMI device by using the notify id (0xd0).
> 
> Signed-off-by: Armin Wolf <W_Armin@....de>
> ---
> Changes since v1:
> - use acpi_dev_name() helper function

I'm a bit divided on this patch. I agree the new way of doing
things is better, but technically this is a bit of a userspace API
break.

I guess we could hope that nothing depends on the old netlink API
format / name but I'm not sure we can rely on that ...

Ilpo, Andy do you have any opinion on this ?

Regards,

Hans




> ---
>  drivers/platform/x86/wmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index a7cfcbf92432..c61860db66ed 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1202,7 +1202,7 @@ static int wmi_notify_device(struct device *dev, void *data)
>  	}
> 
>  	acpi_bus_generate_netlink_event(wblock->acpi_device->pnp.device_class,
> -					dev_name(&wblock->dev.dev), *event, 0);
> +					acpi_dev_name(wblock->acpi_device), *event, 0);
> 
>  	return -EBUSY;
>  }
> --
> 2.39.2
>