ACPI video: if no ACPI backlight support, use vendor drivers

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: Thomas Renninger <trenn@suse.de>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index fd6a452b0ceb..7f23761ace35 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -194,6 +194,50 @@ extern bool wmi_has_guid(const char *guid);
 
 #endif  /* CONFIG_ACPI_WMI */
 
+#define ACPI_VIDEO_OUTPUT_SWITCHING                     0x0001
+#define ACPI_VIDEO_DEVICE_POSTING                       0x0002
+#define ACPI_VIDEO_ROM_AVAILABLE                        0x0004
+#define ACPI_VIDEO_BACKLIGHT                            0x0008
+#define ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR               0x0010
+#define ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO                0x0020
+#define ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR        0x0040
+#define ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO         0x0080
+#define ACPI_VIDEO_BACKLIGHT_DMI_VENDOR                 0x0100
+#define ACPI_VIDEO_BACKLIGHT_DMI_VIDEO                  0x0200
+#define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR          0x0400
+#define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO           0x0800
+
+#if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE)
+
+extern long acpi_video_get_capabilities(acpi_handle graphics_dev_handle);
+extern long acpi_is_video_device(struct acpi_device *device);
+extern int acpi_video_backlight_support(void);
+extern int acpi_video_display_switch_support(void);
+
+#else
+
+static inline long acpi_video_get_capabilities(acpi_handle graphics_dev_handle)
+{
+        return 0;
+}
+
+static inline long acpi_is_video_device(struct acpi_device *device)
+{
+        return 0;
+}
+
+static inline int acpi_video_backlight_support(void)
+{
+        return 0;
+}
+
+static inline int acpi_video_display_switch_support(void)
+{
+        return 0;
+}
+
+#endif /* defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE) */
+
 extern int acpi_blacklisted(void);
 #ifdef CONFIG_DMI
 extern void acpi_dmi_osi_linux(int enable, const struct dmi_system_id *d);