Commit f838eb5b authored by Corentin Chary's avatar Corentin Chary Committed by Matthew Garrett
Browse files

acpi: add a way to promote/demote vendor backlight drivers 



Instead of adding a big blacklist in video_detect.c to set
ACPI_VIDEO_BACKLIGHT_DMI_VENDOR correctly, let external modules
promote or demote themselves when they know the generic video
module won't work.

Currently drivers where using acpi_video_unregister() directly
but:
- That didn't respect any acpi_backlight=[video|vendor] parameter
  provided by the user.
- Any later call to acpi_video_register() would still re-load the
  generic video module (and some gpu drivers are doing that).

This patch fix those two issues.

Signed-off-by: default avatarCorentin Chary <corentin.chary@gmail.com>
Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
parent 1eb3fe1d

drivers/acpi/video_detect.c

+29 −2
Original line number Diff line number Diff line
@@ -182,8 +182,7 @@ long acpi_video_get_capabilities(acpi_handle graphics_handle) 
}

EXPORT_SYMBOL(acpi_video_get_capabilities);



/* Returns true if video.ko can do backlight switching */

int acpi_video_backlight_support(void)

static void acpi_video_caps_check(void)

{

	/*

	 * We must check whether the ACPI graphics device is physically plugged
@@ -191,6 +190,34 @@ int acpi_video_backlight_support(void) 
	 */

	if (!acpi_video_caps_checked)

		acpi_video_get_capabilities(NULL);

}



/* 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

 * 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;

}

EXPORT_SYMBOL(acpi_video_dmi_promote_vendor);



/* To be called when a driver who previously promoted the vendor

 * interface */

void acpi_video_dmi_demote_vendor(void)

{

	acpi_video_caps_check();

	acpi_video_support &= ~ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;

}

EXPORT_SYMBOL(acpi_video_dmi_demote_vendor);



/* 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)

include/linux/acpi.h

+10 −0
Original line number Diff line number Diff line
@@ -190,6 +190,8 @@ extern bool wmi_has_guid(const char *guid); 


extern long acpi_video_get_capabilities(acpi_handle graphics_dev_handle);

extern long acpi_is_video_device(struct acpi_device *device);

extern void acpi_video_dmi_promote_vendor(void);

extern void acpi_video_dmi_demote_vendor(void);

extern int acpi_video_backlight_support(void);

extern int acpi_video_display_switch_support(void);
@@ -205,6 +207,14 @@ static inline long acpi_is_video_device(struct acpi_device *device) 
	return 0;

}



static inline void acpi_video_dmi_promote_vendor(void)

{

}



static inline void acpi_video_dmi_demote_vendor(void)

{

}



static inline int acpi_video_backlight_support(void)

{

	return 0;

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