diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2023-03-07 13:05:40 +0100 |
|---|---|---|
| committer | Hans de Goede <hdegoede@redhat.com> | 2023-03-16 13:33:11 +0100 |
| commit | 3608a2cd818a8d97bd3d4dc32f6c0afaf09b15ec (patch) | |
| tree | 456d6791cc25e151b40b9471bd7be489e6f8fdce /include/linux/apple_bl.h | |
| parent | f0f2903de50418899a5e5dcecf2906da44a7a05e (diff) | |
backlight: apple_bl: Use acpi_video_get_backlight_type()
On some MacBooks both the apple_bl and the apple-gmux backlight drivers
may be able to export a /sys/class/backlight device.
To avoid having 2 backlight devices for one LCD panel until now
the apple-gmux driver has been calling apple_bl_unregister() to move
the apple_bl backlight device out of the way when it loads.
Similar problems exist on other x86 laptops and all backlight drivers
which may be used on x86 laptops have moved to using
acpi_video_get_backlight_type() to determine whether they should load
or not.
Switch apple_bl to this model too, so that it is consistent with all
the other x86 backlight drivers.
Besides code-simplification and consistency this has 2 other benefits:
1) It removes a race during boot where userspace will briefly see
an apple_bl backlight and then have it disappear again, leading to e.g.:
https://bbs.archlinux.org/viewtopic.php?id=269920
2) This allows user to switch between the drivers by passing
acpi_backlight=apple_gmux or acpi_backlight=vendor on the kernel
commandline.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230307120540.389920-1-hdegoede@redhat.com
Diffstat (limited to 'include/linux/apple_bl.h')
| -rw-r--r-- | include/linux/apple_bl.h | 27 |
1 files changed, 0 insertions, 27 deletions
diff --git a/include/linux/apple_bl.h b/include/linux/apple_bl.h deleted file mode 100644 index 445af2e3cc21..000000000000 --- a/include/linux/apple_bl.h +++ /dev/null @@ -1,27 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * apple_bl exported symbols - */ - -#ifndef _LINUX_APPLE_BL_H -#define _LINUX_APPLE_BL_H - -#if defined(CONFIG_BACKLIGHT_APPLE) || defined(CONFIG_BACKLIGHT_APPLE_MODULE) - -extern int apple_bl_register(void); -extern void apple_bl_unregister(void); - -#else /* !CONFIG_BACKLIGHT_APPLE */ - -static inline int apple_bl_register(void) -{ - return 0; -} - -static inline void apple_bl_unregister(void) -{ -} - -#endif /* !CONFIG_BACKLIGHT_APPLE */ - -#endif /* _LINUX_APPLE_BL_H */ |