Re: [PATCH] dell-laptop: add parameter to disable the backlight device.

From: Alex Davis
Date: Sun Dec 08 2013 - 18:43:35 EST



I code, therefore I am

--------------------------------------------
On Sun, 12/8/13, Alex Davis <alex14641@xxxxxxxxx> wrote:

Subject: Re: [PATCH] dell-laptop: add parameter to disable the backlight device.
To: "mjg59@xxxxxxxxxxxxx" <mjg59@xxxxxxxxxxxxx>, "linux-kernel@xxxxxxxxxxxxxxx" <linux-kernel@xxxxxxxxxxxxxxx>, "Levente Kurusa" <levex@xxxxxxxxx>
Date: Sunday, December 8, 2013, 3:38 PM



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On Sun, 12/8/13, Levente Kurusa <levex@xxxxxxxxx>
wrote:

> Subject: Re: [PATCH] dell-laptop: add parameter to
disable the backlight device.
> To: "Alex Davis" <alex14641@xxxxxxxxx>,
"mjg59@xxxxxxxxxxxxx"
<mjg59@xxxxxxxxxxxxx>,
>"linux->kernel@xxxxxxxxxxxxxxx"
<linux-kernel@xxxxxxxxxxxxxxx>
> Date: Sunday, December 8, 2013, 9:06 AM


>>2013-12-08 14:40, Alex Davis:
>> I have a Dell Inspiron N7010 Laptop with Intel
graphics. When the dell-laptop module is loaded,
>> two backlight device devices are created;
dell_backlight, and intel_backlight from the Intel
>> graphics driver. The dell_backlight device is
non-functional, but the graphics subsystem uses
>> it instead of the functioning intel_backlight
device.
The result is that, when running KDE,
>> screen brightness cannot be controlled. I've added
a
module parameter, disable_backlight
>> which, when true, will disable the dell_backlight
device, and leave only the intel_backlight:
>> with this, screen brightness can be controlled.
>>

> Hi,

>I think it would be better if we could figure out why
the
>dell_blacklight device is not working rather than
disabling
>it.


> Regarding your patch, it creates a memory leak as you:
>  * allocate a platform device
>  * you add it
>  * you allocated a page for SMI
>
> Your if(disable_blacklight) code should go
> where it checks the DMI.
>
> -- Regards,
> Levente Kurusa

Levante,

>You are correct. The existing code also has a memory leak. I
>will submit a patch for that.

Upon further investigation, I'm not seeing the memory leak. I see the objects being allocated, but they are deallocated in the dell_exit method.



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