Until now, the dell-wmi-ddv driver needs to be manually
patched and compiled to test compatibility with unknown
DDV WMI interface versions.
Add a module param to allow users to force loading even
when a unknown interface version was detected. Since this
might cause various unwanted side effects, the module param
is marked as unsafe.
Also update kernel-parameters.txt.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 Documentation/admin-guide/kernel-parameters.txt |  3 +++
 drivers/platform/x86/dell/dell-wmi-ddv.c        | 13 +++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6cfa6e3996cf..9bbff5113427 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1024,6 +1024,9 @@
 	dell_smm_hwmon.fan_max=
 			[HW] Maximum configurable fan speed.

+	dell_wmi_ddv.force=
+			[HW] Do not check for supported WMI interface versions.
+
 	dfltcc=		[HW,S390]
 			Format: { on | off | def_only | inf_only | always }
 			on:       s390 zlib hardware support for compression on
diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
index 58fadb74e86a..9695bf493ea6 100644
--- a/drivers/platform/x86/dell/dell-wmi-ddv.c
+++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
@@ -34,6 +34,10 @@
 #define DELL_EPPID_LENGTH	20
 #define DELL_EPPID_EXT_LENGTH	23

+static bool force;
+module_param_unsafe(force, bool, 0);
+MODULE_PARM_DESC(force, "Force loading without checking for supported WMI interface versions");
+
 enum dell_ddv_method {
 	DELL_DDV_BATTERY_DESIGN_CAPACITY	= 0x01,
 	DELL_DDV_BATTERY_FULL_CHARGE_CAPACITY	= 0x02,
@@ -349,8 +353,13 @@ static int dell_wmi_ddv_probe(struct wmi_device *wdev, const void *context)
 		return ret;

 	dev_dbg(&wdev->dev, "WMI interface version: %d\n", version);
-	if (version < DELL_DDV_SUPPORTED_VERSION_MIN || version > DELL_DDV_SUPPORTED_VERSION_MAX)
-		return -ENODEV;
+	if (version < DELL_DDV_SUPPORTED_VERSION_MIN || version > DELL_DDV_SUPPORTED_VERSION_MAX) {
+		if (!force)
+			return -ENODEV;
+
+		dev_warn(&wdev->dev, "Loading despite unsupported WMI interface version (%u)\n",
+			 version);
+	}

 	data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
--
2.30.2

Hi again,

On 1/26/23 20:40, Armin Wolf wrote:
> Until now, the dell-wmi-ddv driver needs to be manually
> patched and compiled to test compatibility with unknown
> DDV WMI interface versions.
> Add a module param to allow users to force loading even
> when a unknown interface version was detected. Since this
> might cause various unwanted side effects, the module param
> is marked as unsafe.
> Also update kernel-parameters.txt.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
>  Documentation/admin-guide/kernel-parameters.txt |  3 +++
>  drivers/platform/x86/dell/dell-wmi-ddv.c        | 13 +++++++++++--
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6cfa6e3996cf..9bbff5113427 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1024,6 +1024,9 @@
>  	dell_smm_hwmon.fan_max=
>  			[HW] Maximum configurable fan speed.
> 
> +	dell_wmi_ddv.force=
> +			[HW] Do not check for supported WMI interface versions.
> +
>  	dfltcc=		[HW,S390]
>  			Format: { on | off | def_only | inf_only | always }
>  			on:       s390 zlib hardware support for compression on

In my previous email I forgot to add that I have dropped this bit. I appreciate
the effort to document this parameter, but if we add documentation for all
existing parameters to Documentation/admin-guide/kernel-parameters.txt then
the file will become quite unyielding / unusable.

So in general we only add new parameters which we expect to be important for
a large group of users or necessary to debug serious problems like machines
not booting.

I realize that a bunch of parameters in there do not match this, like
e.g. dell_smm_hwmon.fan_max, these are just from older times when
there were just less parameters, so listing them all was still ok.

So I have merged this patch, but with the Documentation/admin-guide/kernel-parameters.txt
bit dropped.

Regards,

Hans






> diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
> index 58fadb74e86a..9695bf493ea6 100644
> --- a/drivers/platform/x86/dell/dell-wmi-ddv.c
> +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
> @@ -34,6 +34,10 @@
>  #define DELL_EPPID_LENGTH	20
>  #define DELL_EPPID_EXT_LENGTH	23
> 
> +static bool force;
> +module_param_unsafe(force, bool, 0);
> +MODULE_PARM_DESC(force, "Force loading without checking for supported WMI interface versions");
> +
>  enum dell_ddv_method {
>  	DELL_DDV_BATTERY_DESIGN_CAPACITY	= 0x01,
>  	DELL_DDV_BATTERY_FULL_CHARGE_CAPACITY	= 0x02,
> @@ -349,8 +353,13 @@ static int dell_wmi_ddv_probe(struct wmi_device *wdev, const void *context)
>  		return ret;
> 
>  	dev_dbg(&wdev->dev, "WMI interface version: %d\n", version);
> -	if (version < DELL_DDV_SUPPORTED_VERSION_MIN || version > DELL_DDV_SUPPORTED_VERSION_MAX)
> -		return -ENODEV;
> +	if (version < DELL_DDV_SUPPORTED_VERSION_MIN || version > DELL_DDV_SUPPORTED_VERSION_MAX) {
> +		if (!force)
> +			return -ENODEV;
> +
> +		dev_warn(&wdev->dev, "Loading despite unsupported WMI interface version (%u)\n",
> +			 version);
> +	}
> 
>  	data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
> --
> 2.30.2
>

Hi again...

On 1/30/23 16:09, Hans de Goede wrote:
> Hi again,
> 
> On 1/26/23 20:40, Armin Wolf wrote:
>> Until now, the dell-wmi-ddv driver needs to be manually
>> patched and compiled to test compatibility with unknown
>> DDV WMI interface versions.
>> Add a module param to allow users to force loading even
>> when a unknown interface version was detected. Since this
>> might cause various unwanted side effects, the module param
>> is marked as unsafe.
>> Also update kernel-parameters.txt.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>>  Documentation/admin-guide/kernel-parameters.txt |  3 +++
>>  drivers/platform/x86/dell/dell-wmi-ddv.c        | 13 +++++++++++--
>>  2 files changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 6cfa6e3996cf..9bbff5113427 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -1024,6 +1024,9 @@
>>  	dell_smm_hwmon.fan_max=
>>  			[HW] Maximum configurable fan speed.
>>
>> +	dell_wmi_ddv.force=
>> +			[HW] Do not check for supported WMI interface versions.
>> +
>>  	dfltcc=		[HW,S390]
>>  			Format: { on | off | def_only | inf_only | always }
>>  			on:       s390 zlib hardware support for compression on
> 
> In my previous email I forgot to add that I have dropped this bit. I appreciate
> the effort to document this parameter, but if we add documentation for all
> existing parameters to Documentation/admin-guide/kernel-parameters.txt then
> the file will become quite unyielding / unusable.
> 
> So in general we only add new parameters which we expect to be important for
> a large group of users or necessary to debug serious problems like machines
> not booting.
> 
> I realize that a bunch of parameters in there do not match this, like
> e.g. dell_smm_hwmon.fan_max, these are just from older times when
> there were just less parameters, so listing them all was still ok.
> 
> So I have merged this patch, but with the Documentation/admin-guide/kernel-parameters.txt
> bit dropped.

I forgot to add: and these days it is really easy to find all the supported parameters
for a module by just doing "modinfo <modulename>

Regards,

Hans

Hi,

On 1/26/23 20:40, Armin Wolf wrote:
> Until now, the dell-wmi-ddv driver needs to be manually
> patched and compiled to test compatibility with unknown
> DDV WMI interface versions.
> Add a module param to allow users to force loading even
> when a unknown interface version was detected. Since this
> might cause various unwanted side effects, the module param
> is marked as unsafe.
> Also update kernel-parameters.txt.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans


> ---
>  Documentation/admin-guide/kernel-parameters.txt |  3 +++
>  drivers/platform/x86/dell/dell-wmi-ddv.c        | 13 +++++++++++--
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6cfa6e3996cf..9bbff5113427 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1024,6 +1024,9 @@
>  	dell_smm_hwmon.fan_max=
>  			[HW] Maximum configurable fan speed.
> 
> +	dell_wmi_ddv.force=
> +			[HW] Do not check for supported WMI interface versions.
> +
>  	dfltcc=		[HW,S390]
>  			Format: { on | off | def_only | inf_only | always }
>  			on:       s390 zlib hardware support for compression on
> diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
> index 58fadb74e86a..9695bf493ea6 100644
> --- a/drivers/platform/x86/dell/dell-wmi-ddv.c
> +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
> @@ -34,6 +34,10 @@
>  #define DELL_EPPID_LENGTH	20
>  #define DELL_EPPID_EXT_LENGTH	23
> 
> +static bool force;
> +module_param_unsafe(force, bool, 0);
> +MODULE_PARM_DESC(force, "Force loading without checking for supported WMI interface versions");
> +
>  enum dell_ddv_method {
>  	DELL_DDV_BATTERY_DESIGN_CAPACITY	= 0x01,
>  	DELL_DDV_BATTERY_FULL_CHARGE_CAPACITY	= 0x02,
> @@ -349,8 +353,13 @@ static int dell_wmi_ddv_probe(struct wmi_device *wdev, const void *context)
>  		return ret;
> 
>  	dev_dbg(&wdev->dev, "WMI interface version: %d\n", version);
> -	if (version < DELL_DDV_SUPPORTED_VERSION_MIN || version > DELL_DDV_SUPPORTED_VERSION_MAX)
> -		return -ENODEV;
> +	if (version < DELL_DDV_SUPPORTED_VERSION_MIN || version > DELL_DDV_SUPPORTED_VERSION_MAX) {
> +		if (!force)
> +			return -ENODEV;
> +
> +		dev_warn(&wdev->dev, "Loading despite unsupported WMI interface version (%u)\n",
> +			 version);
> +	}
> 
>  	data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
> --
> 2.30.2
>