Linux/ACPI core files using internal.h all PREFIX "ACPI: ",
however, not all ACPI drivers use/want it -- and they
should not have to #undef PREFIX to define their own.

Add GPL commment to internal.h while we are there.

This does not change any actual console output,
asside from a whitespace fix.
Signed-off-by: NLen Brown <len.brown@intel.com>

Now that acpi_get_pci_dev is available, let's use it instead of
acpi_get_physical_pci_device()

Cc: Thomas Renninger <trenn@suse.de>
Signed-off-by: NAlex Chiang <achiang@hp.com>
Acked-by: NBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

ACPI backlight control w/o _BQC support is kinda firmware bug.
Add a warning if _BQC is not implemented.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

Sparse asked whether these could be static.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

If an ACPI graphics device supports backlight brightness functions (cmp. with
latest ACPI spec Appendix B), let the ACPI video driver control backlight and
switch backlight control off in vendor specific ACPI drivers (asus_acpi,
thinkpad_acpi, eeepc, fujitsu_laptop, msi_laptop, sony_laptop, acer-wmi).

Currently it is possible to load above drivers and let both poke on the
brightness HW registers, the video and vendor specific ACPI drivers -> bad.

This patch provides the basic support to check for BIOS capabilities before
driver loading time. Driver specific modifications are in separate follow up
patches.

"acpi_backlight=vendor"
	Prever vendor driver over ACPI driver for backlight.
"acpi_backlight=video" (default)
	Prever ACPI driver over vendor driver for backlight.
Signed-off-by: NThomas Renninger <trenn@suse.de>
Acked-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>