linux-kernel - Re: [PATCH 1/2] platform/x86: wmi: Fix WMI event enablement

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e23ffd29-13db-bb11-ee06-0f1203269902@linux.intel.com>
Date: Wed, 25 Jun 2025 15:28:43 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Armin Wolf <W_Armin@....de>
cc: dimich.dmb@...il.com, Hans de Goede <hdegoede@...hat.com>, 
    kuurtb@...il.com, corbet@....net, platform-driver-x86@...r.kernel.org, 
    LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] platform/x86: wmi: Fix WMI event enablement

On Fri, 20 Jun 2025, Armin Wolf wrote:

> It turns out that the Windows WMI-ACPI driver always enables/disables
> WMI events regardless of whether they are marked as expensive or not.
> This finding is further reinforced when reading the documentation of
> the WMI_FUNCTION_CONTROL_CALLBACK callback used by Windows drivers
> for enabling/disabling WMI devices:
> 
> 	The DpWmiFunctionControl routine enables or disables
> 	notification of events, and enables or disables data
> 	collection for data blocks that the driver registered
> 	as expensive to collect.
> 
> Follow this behavior to fix the WMI event used for reporting hotkey
> events on the Dell Latitude 5400 and likely many more devices.
> 
> Reported-by: Dmytro Bagrii <dimich.dmb@...il.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220246
> Tested-by: Dmytro Bagrii <dimich.dmb@...il.com>
> Fixes: 656f0961d126 ("platform/x86: wmi: Rework WCxx/WExx ACPI method handling")
> Signed-off-by: Armin Wolf <W_Armin@....de>
> ---
>  drivers/platform/x86/wmi.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 21b7e54bd7ab..4e86a422f05f 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -180,16 +180,22 @@ static int wmi_device_enable(struct wmi_device *wdev, bool enable)
>  	acpi_handle handle;
>  	acpi_status status;
>  
> -	if (!(wblock->gblock.flags & ACPI_WMI_EXPENSIVE))
> -		return 0;
> -
>  	if (wblock->dev.dev.type == &wmi_type_method)
>  		return 0;
>  
> -	if (wblock->dev.dev.type == &wmi_type_event)
> +	if (wblock->dev.dev.type == &wmi_type_event) {
> +		/*
> +		 * Windows always enables/disables WMI events, even when they are
> +		 * not marked as being expensive. We follow this behavior for

Hi Armin,

Is the wording in the comment reversed? (I suspect you didn't mean to 
include "not" into that statement?)

> +		 * compatibility reasons.
> +		 */
>  		snprintf(method, sizeof(method), "WE%02X", wblock->gblock.notify_id);
> -	else
> +	} else {
> +		if (!(wblock->gblock.flags & ACPI_WMI_EXPENSIVE))
> +			return 0;
> +
>  		get_acpi_method_name(wblock, 'C', method);
> +	}
>  
>  	/*
>  	 * Not all WMI devices marked as expensive actually implement the
> 

-- 
 i.