Re: [PATCH] Platform: add Samsung Laptop platform driver

[Matthew Garrett]

On Sun, Mar 13, 2011 at 09:17:53AM -0700, Greg KH wrote:
> On Sun, Mar 13, 2011 at 12:03:20PM +0200, Nikolai Kondrashov wrote:
> > Sometime ago I've found this hack on some forum, which I use currently
> > to set the brightness:
> > 
> > setpci -s 00:02.0 f4.b="$HEX_BYTE"
> > 
> > It allows finer control of the brightness, but it seems it operates directly
> > on the video card PCI register. I assume there is no sane way to use
> > this interface from the platform driver, right?
> 
> Yes, do not do this, it causes all sorts of problems in the end, not the
> least being the BIOS doesn't know what is going on at all as you are
> changing the brightness without it knowing it.

It's also modifying configuration that belongs to a device being managed 
by another driver, so it's the kind of thing we frown upon. Having said 
that, the Intel driver should gain native backlight support in .39.

-- 
Matthew Garrett | mjg59@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/