Re: [PATCH] ACPI: Disable Windows 8 compatibility for some Lenovo ThinkPads

[Aaron Lu <aaron.lu@intel.com>]

On 04/22/2013 09:56 PM, Seth Forshee wrote:
> On Mon, Apr 22, 2013 at 09:40:00PM +0800, Aaron Lu wrote:
>> On 04/22/2013 09:06 PM, Seth Forshee wrote:
>>> On Mon, Apr 22, 2013 at 08:11:17PM +0800, Aaron Lu wrote:
>>>> On 04/22/2013 07:51 PM, Rafael J. Wysocki wrote:
>>>>> I suppose we need to blacklist them to start with.  I wouldn't like to apply
>>>>> any general changes before we know how many different systems are affected by
>>>>> this particular issue.
>>>>
>>>> I totally agree.
>>>
>>> Are you sure that all of these machines have an alternate interface for
>>> userspace to change the brightness? I know that I've got a non-Lenovo
>>> machine with nVidia graphics for which nouveau exposes no backlight
>>
>> What's the problem with this system then? The same as the thinkpads in
>> bug 51231?
>
> There's no problem with that system; it has another working backlight
> interface. I'm only mentioning it to demonstrate that taking away the
> ACPI interface could leave some machines without any backlight control
> mechanism that Linux currently supports.

I think we just need take away the ACPI interface for these known broken
systems for now, that would require: check if we are in win8 mode, if
so, disable acpi video interface for these known broken systems.

I think video_detect_dmi_table is the proper place to do this.

-Aaron