[PATCH 07/32] acpi-video-detect: Rewrite backlight interface selection logic
Aaron Lu
aaron.lu at intel.com
Thu Jun 11 02:00:15 PDT 2015
On Wed, Jun 10, 2015 at 03:01:07PM +0200, Hans de Goede wrote:
> 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_video.backlight=[video|vendor|native|none], and
> adding a new API to video_detect.c to reflect this.
I like backlight=[firmware|platform|raw|none] better, but that would
require to put the selection/quirk logic to backlight core. What do you
think?
Regards,
Aaron
>
> 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 at redhat.com>
> ---
> drivers/acpi/video_detect.c | 172 +++++++++++++++++++++-----------------------
> include/acpi/video.h | 17 +++++
> 2 files changed, 100 insertions(+), 89 deletions(-)
>
> diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
> index 0bc8b98..01c8c46 100644
> --- a/drivers/acpi/video_detect.c
> +++ b/drivers/acpi/video_detect.c
> @@ -1,4 +1,6 @@
> /*
> + * Copyright (C) 2015 Red Hat Inc.
> + * Hans de Goede <hdegoede at redhat.com>
> * Copyright (C) 2008 SuSE Linux Products GmbH
> * Thomas Renninger <trenn at suse.de>
> *
> @@ -9,28 +11,24 @@
> * 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 <acpi/video.h>
> #include <linux/export.h>
> #include <linux/acpi.h>
> +#include <linux/backlight.h>
> #include <linux/dmi.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> @@ -38,20 +36,24 @@
> 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 char acpi_backlight_str[16];
> module_param_string(backlight, acpi_backlight_str, 16, 0444);
> MODULE_PARM_DESC(backlight,
> - "Select which backlight interface to use [vendor|video]");
> + "Select which backlight interface to use [vendor|video|native]");
>
> static void acpi_video_parse_cmdline(void)
> {
> if (!strcmp("vendor", acpi_backlight_str))
> - acpi_video_support |= ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
> + acpi_backlight_cmdline = acpi_backlight_vendor;
> if (!strcmp("video", acpi_backlight_str))
> - acpi_video_support |= ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
> + acpi_backlight_cmdline = acpi_backlight_video;
> + if (!strcmp("native", acpi_backlight_str))
> + acpi_backlight_cmdline = acpi_backlight_native;
> + if (!strcmp("none", acpi_backlight_str))
> + acpi_backlight_cmdline = acpi_backlight_none;
> }
>
> static acpi_status
> @@ -82,7 +84,7 @@ 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;
> }
>
> @@ -130,99 +132,91 @@ static 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.
> + *
> + * 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 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.
> + * 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;
> -
> - 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.:
> - *
> - * if (dmi_name_in_vendors("XY")) {
> - * acpi_video_support |=
> - * ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
> - *}
> - */
> + 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)
> +/*
> + * 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)
> {
> - /*
> - * 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);
> - }
> + 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);
> diff --git a/include/acpi/video.h b/include/acpi/video.h
> index 843ef1a..01b5cc7 100644
> --- a/include/acpi/video.h
> +++ b/include/acpi/video.h
> @@ -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
> --
> 2.4.2
>
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