Re: [PATCH 3/4] ACPI: thinkpad-acpi: disable backlight handler if ACPI generic could do it

[Thomas Renninger <trenn@suse.de>]

On Tue, 2007-10-09 at 10:47 -0300, Henrique de Moraes Holschuh wrote:
> On Tue, 09 Oct 2007, Thomas Renninger wrote:
> > > Error prone how?  Please expand, because right now I am not inclined to
> > > remove that variable.  It is optional, and disabled by default.  Distros are
> > > not going to enable it unless they have a damn good reason to, and it is not
> > > even something that one can enable at runtime.
> > > 
> > > Should I make the help text stronger against enabling the option? Is it not
> > > clear enough?
> >
> > No, all the _BCL poking should vanish.
> 
> I need to *somehow* find out if the thinkpad supports the video extensions.

Maybe in scan.c:acpi_video_bus_match() we could add a quirk like:

if (ThinkPad){
 if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_BCM", &h_dummy1)) &&
 ACPI_SUCCESS(acpi_get_handle(device->handle, "_BCL", &h_dummy2))) &&
 return 0;
else
 return -ENODEV;

This would make the video module only load on thinkpads if the
brightness functions are implemented.
Then the double register could work with this one check, or you are
right, it needs to be checked again in the thinkpad module explicitly.

   Thomas