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![Hans de Goede](/assets/img/avatar_default.png)
On machins without an i915 opregion the acpi_video driver immediately probes the ACPI video bus and used to also immediately register acpi_video# backlight devices when supported. Once the drm/kms driver then loaded later and possibly registered a native backlight device then the drivers/acpi/video_detect.c code unregistered the acpi_video0 device to avoid there being 2 backlight devices (when acpi_video_get_backlight_type()==native). This means that userspace used to briefly see 2 devices and the disappearing of acpi_video0 after a brief time confuses the systemd backlight level save/restore code, see e.g.: https://bbs.archlinux.org/viewtopic.php?id=269920 To fix this the ACPI video code has been modified to make backlight class device registration a separate step, relying on the drm/kms driver to ask for the acpi_video backlight registration after it is done setting up its native backlight device. Add a call to the new acpi_video_register_backlight() after the i915 calls acpi_video_register() (after setting up the i915 opregion) so that the acpi_video backlight devices get registered on systems where the i915 native backlight device is not registered. Changes in v2: -Only call acpi_video_register_backlight() when a panel is detected Changes in v3: -Add a new intel_acpi_video_register() helper which checks if a panel is present and then calls acpi_video_register_backlight() Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
31 lines
1.1 KiB
C
31 lines
1.1 KiB
C
/* SPDX-License-Identifier: MIT */
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/*
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* Copyright © 2019 Intel Corporation
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*/
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#ifndef __INTEL_ACPI_H__
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#define __INTEL_ACPI_H__
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struct drm_i915_private;
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#ifdef CONFIG_ACPI
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void intel_register_dsm_handler(void);
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void intel_unregister_dsm_handler(void);
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void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915);
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void intel_acpi_device_id_update(struct drm_i915_private *i915);
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void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915);
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void intel_acpi_video_register(struct drm_i915_private *i915);
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#else
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static inline void intel_register_dsm_handler(void) { return; }
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static inline void intel_unregister_dsm_handler(void) { return; }
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static inline
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void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915) { return; }
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static inline
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void intel_acpi_device_id_update(struct drm_i915_private *i915) { return; }
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static inline
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void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915) { return; }
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static inline
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void intel_acpi_video_register(struct drm_i915_private *i915) { return; }
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#endif /* CONFIG_ACPI */
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#endif /* __INTEL_ACPI_H__ */
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