acpi-video-detect: video: Make video_detect code part of the video module

This is a preparation patch for the backlight interface selection logic
cleanup, there are 2 reasons to not always build the video_detect code
into the kernel:

1) In order for the video_detect.c to also deal with / select native
backlight interfaces on win8 systems, instead of doing this in video.c
where it does not belong, video_detect.c needs to call into the backlight
class code. Which cannot be done if it is builtin and the blacklight class
is not.

2) Currently all the platform/x86 drivers which have quirks to prefer
the vendor driver over acpi-video call acpi_video_unregister_backlight()
to remove the acpi-video backlight interface, this logic really belongs
in video_detect.c, which will cause video_detect.c to depend on symbols of
video.c and video.c already depends on video_detect.c symbols, so they
really need to be a single module.

Note that this commits make 2 changes so as to maintain 100% kernel
commandline compatibility:

1) The __setup call for the acpi_backlight= handling is moved to
acpi/util.c as __setup may only be used by code which is alwasy builtin
2) video.c is renamed to acpi_video.c so that it can be combined with
video_detect.c into video.ko

This commit also makes changes to drivers/platform/x86/Kconfig to ensure
that drivers which use acpi_video_backlight_support() from video_detect.c,
will not be built-in when acpi_video is not built in. This also changes
some "select" uses to "depends on" to avoid dependency loops.

Signed-off-by: Hans de Goede <[e-mail]>
Acked-by: Darren Hart <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/Makefile

···
 acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
 acpi-$(CONFIG_ACPI_NUMA)	+= numa.o
 acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
-ifdef CONFIG_ACPI_VIDEO
-acpi-y				+= video_detect.o
-endif
 acpi-y				+= acpi_lpat.o
 acpi-$(CONFIG_ACPI_GENERIC_GSI) += gsi.o
 
···
 obj-$(CONFIG_PMIC_OPREGION)	+= pmic/intel_pmic.o
 obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
 obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
+
+video-objs			+= acpi_video.o video_detect.o

drivers/acpi/utils.c

···
 	return false;
 }
 EXPORT_SYMBOL(acpi_check_dsm);
+
+/*
+ * acpi_backlight= handling, this is done here rather then in video_detect.c
+ * because __setup cannot be used in modules.
+ */
+char acpi_video_backlight_string[16];
+EXPORT_SYMBOL(acpi_video_backlight_string);
+
+static int __init acpi_backlight(char *str)
+{
+	strlcpy(acpi_video_backlight_string, str,
+		sizeof(acpi_video_backlight_string));
+	return 1;
+}
+__setup("acpi_backlight=", acpi_backlight);

drivers/acpi/video.c drivers/acpi/acpi_video.c

···
 #include <acpi/video.h>
 #include <asm/uaccess.h>
 
-#include "internal.h"
+#define PREFIX "ACPI: "
 
 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
 #define ACPI_VIDEO_DEVICE_NAME		"Video Device"

drivers/acpi/video_detect.c

···
 #include <linux/export.h>
 #include <linux/acpi.h>
 #include <linux/dmi.h>
+#include <linux/module.h>
 #include <linux/pci.h>
-
-#include "internal.h"
 
 ACPI_MODULE_NAME("video");
 #define _COMPONENT		ACPI_VIDEO_COMPONENT
 
 static long acpi_video_support;
 static bool acpi_video_caps_checked;
+
+static void acpi_video_parse_cmdline(void)
+{
+	if (!strcmp("vendor", acpi_video_backlight_string))
+		acpi_video_support |= ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
+	if (!strcmp("video", acpi_video_backlight_string))
+		acpi_video_support |= ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
+}
 
 static acpi_status
 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
···
 	 * We must check whether the ACPI graphics device is physically plugged
 	 * in. Therefore this must be called after binding PCI and ACPI devices
 	 */
-	if (!acpi_video_caps_checked)
+	if (!acpi_video_caps_checked) {
+		acpi_video_parse_cmdline();
 		acpi_video_get_capabilities(NULL);
+	}
 }
 
 /* Promote the vendor interface instead of the generic video module.
···
 	return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 }
 EXPORT_SYMBOL(acpi_video_backlight_support);
-
-/*
- * Use acpi_backlight=vendor/video to force that backlight switching
- * is processed by vendor specific acpi drivers or video.ko driver.
- */
-static int __init acpi_backlight(char *str)
-{
-	if (str == NULL || *str == '\0')
-		return 1;
-	else {
-		if (!strcmp("vendor", str))
-			acpi_video_support |=
-				ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
-		if (!strcmp("video", str))
-			acpi_video_support |=
-				ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
-	}
-	return 1;
-}
-__setup("acpi_backlight=", acpi_backlight);

drivers/platform/x86/Kconfig

···
 	depends on ACPI
 	select LEDS_CLASS
 	select NEW_LEDS
-	select BACKLIGHT_CLASS_DEVICE
+	depends on BACKLIGHT_CLASS_DEVICE
 	depends on INPUT
 	depends on RFKILL || RFKILL = n
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	select INPUT_SPARSEKMAP
 	select INPUT_POLLDEV
 	---help---
···
 	depends on X86
 	depends on DCDBAS
 	depends on BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL || RFKILL = n
 	depends on SERIO_I8042
 	select POWER_SUPPLY
···
 	tristate "Dell WMI extras"
 	depends on ACPI_WMI
 	depends on INPUT
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	select INPUT_SPARSEKMAP
 	---help---
 	  Say Y here if you want to support WMI-based hotkeys on Dell laptops.
···
 	depends on ACPI
 	depends on INPUT
 	depends on BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on LEDS_CLASS || LEDS_CLASS=n
 	---help---
 	  This is a driver for laptops built by Fujitsu:
···
 	tristate "MSI Laptop Extras"
 	depends on ACPI
 	depends on BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL
 	depends on INPUT && SERIO_I8042
 	select INPUT_SPARSEKMAP
···
 	tristate "Compal (and others) Laptop Extras"
 	depends on ACPI
 	depends on BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL
 	depends on HWMON
 	depends on POWER_SUPPLY
···
 config SONY_LAPTOP
 	tristate "Sony Laptop Extras"
 	depends on ACPI
-	select BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
+	depends on BACKLIGHT_CLASS_DEVICE
 	depends on INPUT
 	depends on RFKILL
 	  ---help---
···
 	depends on RFKILL && INPUT
 	depends on SERIO_I8042
 	depends on BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	select INPUT_SPARSEKMAP
 	help
 	  This is a driver for Lenovo IdeaPad netbooks contains drivers for
···
 	depends on ACPI
 	depends on INPUT
 	depends on RFKILL || RFKILL = n
-	select BACKLIGHT_LCD_SUPPORT
-	select BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
+	depends on BACKLIGHT_CLASS_DEVICE
 	select HWMON
 	select NVRAM
 	select NEW_LEDS
···
 	depends on ACPI
 	depends on INPUT
 	depends on RFKILL || RFKILL = n
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on HOTPLUG_PCI
-	select BACKLIGHT_CLASS_DEVICE
+	depends on BACKLIGHT_CLASS_DEVICE
 	select HWMON
 	select LEDS_CLASS
 	select NEW_LEDS
···
 	depends on ACPI_WMI
 	depends on INPUT
 	depends on BACKLIGHT_CLASS_DEVICE
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	select INPUT_SPARSEKMAP
 	help
 	 Say Y here if you want to support WMI-based hotkeys on MSI laptops.
···
 config INTEL_OAKTRAIL
 	tristate "Intel Oaktrail Platform Extras"
 	depends on ACPI
+	depends on ACPI_VIDEO || ACPI_VIDEO = n
 	depends on RFKILL && BACKLIGHT_CLASS_DEVICE && ACPI
 	---help---
 	  Intel Oaktrail platform need this driver to provide interfaces to

include/linux/acpi.h

···
 #define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR		0x0400
 #define ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO		0x0800
 
+extern char acpi_video_backlight_string[];
 extern long acpi_is_video_device(acpi_handle handle);
 
 #if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE)