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acpi-video-detect: Rewrite backlight interface selection logic

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Currently we have 2 kernel commandline options + dmi-quirks in 3 places all
interacting (in interesting ways) to select which which backlight interface
to use. On the commandline we've acpi_backlight=[video|vendor] and
video.use_native_backlight=[0|1]. DMI quirks we have in
acpi/video-detect.c, acpi/video.c and drivers/platform/x86/*.c .

This commit is the first step to cleaning this up, replacing the 2 cmdline
options with just acpi_backlight=[video|vendor|native|none], and adds a
new API to video_detect.c to reflect this.

Follow up commits will also move other related code, like unregistering the
acpi_video backlight interface if it was registered before other drivers
which take priority over it are loaded, to video_detect.c where this
logic really belongs.

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>
This commit is contained in:
Hans de Goede 2015-06-16 16:27:48 +02:00 committed by Rafael J. Wysocki
parent 14ca7a47d0
commit 87521e16a7
2 changed files with 102 additions and 90 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

175
drivers/acpi/video_detect.c
View File

@ -1,4 +1,6 @@
/*
* 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.
* 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
*
* Arguably the native on win8 check should be done first, but that would
* be a behavior change, which may causes issues.
*/
static long acpi_video_get_capabilities(acpi_handle graphics_handle)
enum acpi_backlight_type acpi_video_get_backlight_type(void)
{
long caps = 0;
struct acpi_device *tmp_dev;
acpi_status status;
static DEFINE_MUTEX(init_mutex);
static bool init_done;
static long video_caps;
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 */
/* 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);
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.:
*
* if (dmi_name_in_vendors("XY")) {
* acpi_video_support |=
* ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
*}
*/
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_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);
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) {
acpi_video_parse_cmdline();
acpi_video_get_capabilities(NULL);
}
}
if (acpi_backlight_cmdline != acpi_backlight_undef)
return acpi_backlight_cmdline;
/* Promote the vendor interface instead of the generic video module.
* This function allow DMI blacklists to be implemented by externals
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);
/*
* 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
*/
void acpi_video_set_dmi_backlight_type(enum acpi_backlight_type type)
{
acpi_backlight_dmi = type;
}
EXPORT_SYMBOL(acpi_video_set_dmi_backlight_type);
/*
* 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);

17
include/acpi/video.h
View File

@ -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