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 <hdegoede@redhat.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 12 insertions, 23 deletions

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index b2270ca21538..bb6133c60175 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -32,16 +32,23 @@
 #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)
 {
@@ -174,8 +181,10 @@ static void acpi_video_caps_check(void)
 	 * 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.
@@ -212,23 +221,3 @@ int acpi_video_backlight_support(void)
 	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);