acpi-video-detect: Rewrite backlight interface selection logic (87521e16) · Commits · 戴 / test

drivers/acpi/video_detect.c

+83 −88

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2015 Red Hat Inc.
		* Hans de Goede <hdegoede@redhat.com>
		* Copyright (C) 2008 SuSE Linux Products GmbH
		* Thomas Renninger <trenn@suse.de>
		*
		@@ -9,44 +11,45 @@
		* acpi_get_pci_dev() can be called to identify ACPI graphics
		* devices for which a real graphics card is plugged in
		*
		* Now acpi_video_get_capabilities() can be called to check which
		* capabilities the graphics cards plugged in support. The check for general
		* video capabilities will be triggered by the first caller of
		* acpi_video_get_capabilities(NULL); which will happen when the first
		* backlight switching supporting driver calls:
		* acpi_video_backlight_support();
		*
		* Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
		* are available, video.ko should be used to handle the device.
		*
		* Otherwise vendor specific drivers like thinkpad_acpi, asus-laptop,
		* sony_acpi,... can take care about backlight brightness.
		*
		* If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
		* this file will not be compiled, acpi_video_get_capabilities() and
		* acpi_video_backlight_support() will always return 0 and vendor specific
		* drivers always can handle backlight.
		* Backlight drivers can use acpi_video_get_backlight_type() to determine
		* which driver should handle the backlight.
		*
		* If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
		* this file will not be compiled and acpi_video_get_backlight_type() will
		* always return acpi_backlight_vendor.
		*/

		#include <linux/export.h>
		#include <linux/acpi.h>
		#include <linux/backlight.h>
		#include <linux/dmi.h>
		#include <linux/module.h>
		#include <linux/pci.h>
		#include <linux/types.h>
		#include <acpi/video.h>

		ACPI_MODULE_NAME("video");
		#define _COMPONENT ACPI_VIDEO_COMPONENT

		static long acpi_video_support;
		static bool acpi_video_caps_checked;
		static enum acpi_backlight_type acpi_backlight_cmdline = acpi_backlight_undef;
		static enum acpi_backlight_type acpi_backlight_dmi = acpi_backlight_undef;

		static void acpi_video_parse_cmdline(void)
		{
		if (!strcmp("vendor", acpi_video_backlight_string))
		acpi_video_support \|= ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
		acpi_backlight_cmdline = acpi_backlight_vendor;
		if (!strcmp("video", acpi_video_backlight_string))
		acpi_video_support \|= ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
		acpi_backlight_cmdline = acpi_backlight_video;
		if (!strcmp("native", acpi_video_backlight_string))
		acpi_backlight_cmdline = acpi_backlight_native;
		if (!strcmp("none", acpi_video_backlight_string))
		acpi_backlight_cmdline = acpi_backlight_none;
		}

		static acpi_status
		@@ -77,7 +80,7 @@ find_video(acpi_handle handle, u32 lvl, void context, void *rv)
		* buggy */
		static int video_detect_force_vendor(const struct dmi_system_id *d)
		{
		acpi_video_support \|= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
		acpi_backlight_dmi = acpi_backlight_vendor;
		return 0;
		}

		@@ -125,99 +128,91 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
		};

		/*
		* Returns the video capabilities of a specific ACPI graphics device
		* Determine which type of backlight interface to use on this system,
		* First check cmdline, then dmi quirks, then do autodetect.
		*
		* if NULL is passed as argument all ACPI devices are enumerated and
		* all graphics capabilities of physically present devices are
		* summarized and returned. This is cached and done only once.
		*/
		static long acpi_video_get_capabilities(acpi_handle graphics_handle)
		{
		long caps = 0;
		struct acpi_device *tmp_dev;
		acpi_status status;

		if (acpi_video_caps_checked && graphics_handle == NULL)
		return acpi_video_support;

		if (!graphics_handle) {
		/* Only do the global walk through all graphics devices once */
		acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
		ACPI_UINT32_MAX, find_video, NULL,
		&caps, NULL);
		/* There might be boot param flags set already... */
		acpi_video_support \|= caps;
		acpi_video_caps_checked = 1;
		/* Add blacklists here. Be careful to use the right DMI bits
		* to still be able to override logic via boot params, e.g.:
		* The autodetect order is:
		* 1) Is the acpi-video backlight interface supported ->
		* no, use a vendor interface
		* 2) Is this a win8 "ready" BIOS and do we have a native interface ->
		* yes, use a native interface
		* 3) Else use the acpi-video interface
		*
		* if (dmi_name_in_vendors("XY")) {
		* acpi_video_support \|=
		* ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
		*}
		* Arguably the native on win8 check should be done first, but that would
		* be a behavior change, which may causes issues.
		*/
		enum acpi_backlight_type acpi_video_get_backlight_type(void)
		{
		static DEFINE_MUTEX(init_mutex);
		static bool init_done;
		static long video_caps;

		/* Parse cmdline, dmi and acpi only once */
		mutex_lock(&init_mutex);
		if (!init_done) {
		acpi_video_parse_cmdline();
		dmi_check_system(video_detect_dmi_table);
		} else {
		status = acpi_bus_get_device(graphics_handle, &tmp_dev);
		if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
		return 0;
		}
		acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
		acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
		ACPI_UINT32_MAX, find_video, NULL,
		&caps, NULL);
		&video_caps, NULL);
		init_done = true;
		}
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
		graphics_handle ? caps : acpi_video_support,
		graphics_handle ? "on device " : "in general",
		graphics_handle ? acpi_device_bid(tmp_dev) : ""));
		return caps;
		mutex_unlock(&init_mutex);

		if (acpi_backlight_cmdline != acpi_backlight_undef)
		return acpi_backlight_cmdline;

		if (acpi_backlight_dmi != acpi_backlight_undef)
		return acpi_backlight_dmi;

		if (!(video_caps & ACPI_VIDEO_BACKLIGHT))
		return acpi_backlight_vendor;

		if (acpi_osi_is_win8() && backlight_device_registered(BACKLIGHT_RAW))
		return acpi_backlight_native;

		return acpi_backlight_video;
		}
		EXPORT_SYMBOL(acpi_video_get_backlight_type);

		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
		* Set the preferred backlight interface type based on DMI info.
		* This function allows DMI blacklists to be implemented by external
		* platform drivers instead of putting a big blacklist in video_detect.c
		*/
		if (!acpi_video_caps_checked) {
		acpi_video_parse_cmdline();
		acpi_video_get_capabilities(NULL);
		}
		void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
		{
		acpi_backlight_dmi = type;
		}
		EXPORT_SYMBOL(acpi_video_set_dmi_backlight_type);

		/* Promote the vendor interface instead of the generic video module.
		* This function allow DMI blacklists to be implemented by externals
		* platform drivers instead of putting a big blacklist in video_detect.c
		/*
		* Compatiblity function, this is going away as soon as all drivers are
		* converted to acpi_video_set_dmi_backlight_type().
		*
		* Promote the vendor interface instead of the generic video module.
		* After calling this function you will probably want to call
		* acpi_video_unregister() to make sure the video module is not loaded
		*/
		void acpi_video_dmi_promote_vendor(void)
		{
		acpi_video_caps_check();
		acpi_video_support \|= ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
		acpi_video_set_dmi_backlight_type(acpi_backlight_vendor);
		}
		EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);

		/* Returns true if video.ko can do backlight switching */
		/*
		* Compatiblity function, this is going away as soon as all drivers are
		* converted to acpi_video_get_backlight_type().
		*
		* Returns true if video.ko can do backlight switching.
		*/
		int acpi_video_backlight_support(void)
		{
		acpi_video_caps_check();

		/* First check for boot param -> highest prio */
		if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
		return 0;
		else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
		return 1;

		/* Then check for DMI blacklist -> second highest prio */
		if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
		return 0;
		else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
		return 1;

		/* Then go the default way */
		return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
		/*
		* This is done this way since vendor drivers call this to see
		* if they should load, and we do not want them to load for both
		* the acpi_backlight_video and acpi_backlight_native cases.
		*/
		return acpi_video_get_backlight_type() != acpi_backlight_vendor;
		}
		EXPORT_SYMBOL(acpi_video_backlight_support);

include/acpi/video.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -16,6 +16,14 @@ struct acpi_device;
		#define ACPI_VIDEO_DISPLAY_LEGACY_PANEL 0x0110
		#define ACPI_VIDEO_DISPLAY_LEGACY_TV 0x0200

		enum acpi_backlight_type {
		acpi_backlight_undef = -1,
		acpi_backlight_none = 0,
		acpi_backlight_video,
		acpi_backlight_vendor,
		acpi_backlight_native,
		};

		#if (defined CONFIG_ACPI_VIDEO \|\| defined CONFIG_ACPI_VIDEO_MODULE)
		extern int acpi_video_register(void);
		extern void acpi_video_unregister(void);
		@@ -23,6 +31,8 @@ extern void acpi_video_unregister_backlight(void);
		extern int acpi_video_get_edid(struct acpi_device *device, int type,
		int device_id, void **edid);
		extern bool acpi_video_verify_backlight_support(void);
		extern enum acpi_backlight_type acpi_video_get_backlight_type(void);
		extern void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type);
		#else
		static inline int acpi_video_register(void) { return 0; }
		static inline void acpi_video_unregister(void) { return; }
		@@ -33,6 +43,13 @@ static inline int acpi_video_get_edid(struct acpi_device *device, int type,
		return -ENODEV;
		}
		static inline bool acpi_video_verify_backlight_support(void) { return false; }
		static inline enum acpi_backlight_type acpi_video_get_backlight_type(void)
		{
		return acpi_backlight_vendor;
		}
		static void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
		{
		}
		#endif

		#endif

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