Re: [PATCH] platform: x86: dell-laptop: Add support for keyboard backlight

[Darren Hart <dvhart@infradead.org>]

On Wed, Nov 19, 2014 at 08:51:28PM +0100, Pali Rohár wrote:
> On Wednesday 19 November 2014 20:23:36 Matthew Garrett wrote:
> > On Wed, Nov 19, 2014 at 10:34:16AM -0800, Darren Hart wrote:
> > > I'm somewhat concerned that this patch doubles the size of
> > > this driver. When we're adding this much code, I have to
> > > ask - does it make sense to grow this driver rather than
> > > create a new one?
> > 
> > There'd be a fair amount of code duplication in splitting it.
> > 
> 
> Yes. dell-laptop.ko implements functions for doing Dell SMBIOS 
> calls which are needed for keyboard backlight.
> 
> > > There is no ACPI backlight driver on these systems? We need
> > > a platform driver?
> > 
> > ACPI doesn't specify keyboard backlight control, so this ends
> > up being very vendor specific.
> 
> dell-laptop.ko is not ACPI driver. It is using Dell SMBIOS calls. 
> And I do not know about Dell specific ACPI interface for keyboard 
> backlight. So Darren, ask this question someone from Dell.

Right, I asked because there is a block in the original driver to defer
to an ACPI backlight driver if it exists. I understand this is a
keyboard backlight driver and is different, but I wanted to check.

So let's go ahead and move forward with dell-laptop.c being the right
place for this addition.

Thanks,

-- 
Darren Hart
Intel Open Source Technology Center