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

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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: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
This commit is contained in:
Corentin Chary 2012-06-13 09:32:01 +02:00 committed by Matthew Garrett
parent 1eb3fe1d3b
commit f838eb5bd2
2 changed files with 39 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

31
drivers/acpi/video_detect.c
View file

@ -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)

10
include/linux/acpi.h
View file

@ -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;