[Intel-gfx] Legacy backlight control with KMS and BACKLIGHT property

[Greg KH]

On Mon, Aug 17, 2009 at 01:41:03AM +0100, Mike Lothian wrote:
> 2009/8/16 Greg KH <greg at kroah.com>:
> > On Sat, Aug 15, 2009 at 01:33:13PM +0100, Mike Lothian wrote:
> >> 2009/8/15 Jesse Barnes <jbarnes at virtuousgeek.org>:
> >> > On Fri, 14 Aug 2009 12:28:47 -0700
> >> > Greg KH <greg at kroah.com> wrote:
> >> >
> >> >> On Fri, Aug 14, 2009 at 12:08:21PM -0700, Greg KH wrote:
> >> >> > Here's a first cut at such a driver.  It works for me on this
> >> >> > laptop, but note that it will try to work on _any_ Intel-based
> >> >> > system.  I'll figure out how to do this only for specific machines
> >> >> > based on DMI data next.
> >> >>
> >> >> And here's one that is set for DMI data to only load on the proper
> >> >> ones.
> >> >>
> >> >> I'll push this upstream now, if there are no objections.
> >> >
> >> > Yeah, looks fairly reasonable.  This code should work on most pre-965
> >> > chipsets too, since they share the LBB regs.  There are a couple of
> >> > other things to take into consideration: I think the VBIOS indicates
> >> > whether the controls are inverted (i.e. a value of 0xff is minimum
> >> > brightness) and there may also be some stepping info.
> >> >
> >> > So ultimately I'd like to see this be part of the i915 driver as one of
> >> > a few different methods supported (hopefully we can autodetect them
> >> > better than the 2D driver though, using the VBIOS and DMI in the
> >> > kernel).
> >> >
> >> > The other three methods that need to export sysfs interfaces are
> >> > OpRegion (already done), i2c (some machines have external controllers;
> >> > the VBIOS describes how to interact with them) and PWM (the "native"
> >> > power modulation regs).
> >>
> >> This is great news guys, hopefully I'll finally be able to control the
> >> screen brightness of my GM45 in my Samsung R510
> >>
> >> If you want a guinea pig to test your code please feel free to forward patches
> >
> > A driver for other Samsung devices is below.  If you think your laptop
> > also works this way (by changing the brightness value by reading and
> > writing the 0xf4 pci config value directly), then we can add support for
> > your laptop to this driver as well, just send me the output of:
> >        lspci
> >        lspci -n
> >        grep . /sys/class/dmi/id/*
> >
> > thanks,
> >
> 
> 
> > +       {
> > +               .ident = "NP-Q45",
> > +               .matches = {
> > +                       DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
> > +                       DMI_MATCH(DMI_PRODUCT_NAME, "SQ45S70S"),
> > +                       DMI_MATCH(DMI_BOARD_NAME, "SQ45S70S"),
> > +               },
> > +               .callback = dmi_check_cb,
> > +       },
> 
> > +        */
> > +       pci_device = pci_get_device(PCI_VENDOR_ID_INTEL, 0x27ae, NULL);
> > +       if (!pci_device) {
> > +               pci_device = pci_get_device(PCI_VENDOR_ID_INTEL, 0x2a02, NULL);
> > +               if (!pci_device)
> > +                       return -ENODEV;
> 
> 
> You are an absolute STAR Greg!!!
> 
> Finally I have brightness control for this laptop on Linux
> 
> I needed to set the DMI names to "R510/P510" and the pci device to
> 0x2a42 but apart from that it works!!!

Care to send me a patch for the driver to add support for this device?

Or just send me the output of:
	grep . /sys/class/dmi/id/*
and I'll add it myself.

thanks,

greg k-h