linux/drivers/gpu/drm/i915/display/intel_panel.h
Lyude Paul 4a8d79901d drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)
So-recently a bunch of laptops on the market have started using DPCD
backlight controls instead of the traditional DDI backlight controls.
Originally we thought we had this handled by adding VESA backlight
control support to i915, but the story ended up being a lot more
complicated then that.

Simply put-there's two main backlight interfaces Intel can see in the
wild. Intel's proprietary HDR backlight interface, and the standard VESA
backlight interface. Note that many panels have been observed to report
support for both backlight interfaces, but testing has shown far more
panels work with the Intel HDR backlight interface at the moment.
Additionally, the VBT appears to be capable of reporting support for the
VESA backlight interface but not the Intel HDR interface which needs to
be probed by setting the right magic OUI.

On top of that however, there's also actually two different variants of
the Intel HDR backlight interface. The first uses the AUX channel for
controlling the brightness of the screen in both SDR and HDR mode, and
the second only uses the AUX channel for setting the brightness level in
HDR mode - relying on PWM for setting the brightness level in SDR mode.

For the time being we've been using EDIDs to maintain a list of quirks
for panels that safely do support the VESA backlight interface. Adding
support for Intel's HDR backlight interface in addition however, should
finally allow us to auto-detect eDP backlight controls properly so long
as we probe like so:

* If the panel's VBT reports VESA backlight support, assume it really
  does support it
* If the panel's VBT reports DDI backlight controls:
  * First probe for Intel's HDR backlight interface
  * If that fails, probe for VESA's backlight interface
  * If that fails, assume no DPCD backlight control
* If the panel's VBT reports any other backlight type: just assume it
  doesn't have DPCD backlight controls

Changes since v4:
* Fix checkpatch issues
Changes since v3:
* Stop using drm_device and use drm_i915_private instead
* Don't forget to return from intel_dp_aux_hdr_get_backlight() if we fail
  to read the current backlight mode from the DPCD
* s/uint8_t/u8/
* Remove unneeded parenthesis in intel_dp_aux_hdr_enable_backlight()
* Use drm_dbg_kms() in intel_dp_aux_init_backlight_funcs()

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Cc: thaytan@noraisin.net
Cc: Vasily Khoruzhick <anarsoul@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210114221709.2261452-4-lyude@redhat.com
2021-01-19 12:35:52 -05:00

71 lines
2.7 KiB
C

/* SPDX-License-Identifier: MIT */
/*
* Copyright © 2019 Intel Corporation
*/
#ifndef __INTEL_PANEL_H__
#define __INTEL_PANEL_H__
#include <linux/types.h>
#include "intel_display.h"
struct drm_connector;
struct drm_connector_state;
struct drm_display_mode;
struct intel_connector;
struct intel_crtc;
struct intel_crtc_state;
struct intel_encoder;
struct intel_panel;
int intel_panel_init(struct intel_panel *panel,
struct drm_display_mode *fixed_mode,
struct drm_display_mode *downclock_mode);
void intel_panel_fini(struct intel_panel *panel);
enum drm_connector_status
intel_panel_detect(struct drm_connector *connector, bool force);
void intel_fixed_panel_mode(const struct drm_display_mode *fixed_mode,
struct drm_display_mode *adjusted_mode);
int intel_pch_panel_fitting(struct intel_crtc_state *crtc_state,
const struct drm_connector_state *conn_state);
int intel_gmch_panel_fitting(struct intel_crtc_state *crtc_state,
const struct drm_connector_state *conn_state);
void intel_panel_set_backlight_acpi(const struct drm_connector_state *conn_state,
u32 level, u32 max);
int intel_panel_setup_backlight(struct drm_connector *connector,
enum pipe pipe);
void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
const struct drm_connector_state *conn_state);
void intel_panel_update_backlight(struct intel_atomic_state *state,
struct intel_encoder *encoder,
const struct intel_crtc_state *crtc_state,
const struct drm_connector_state *conn_state);
void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state);
struct drm_display_mode *
intel_panel_edid_downclock_mode(struct intel_connector *connector,
const struct drm_display_mode *fixed_mode);
struct drm_display_mode *
intel_panel_edid_fixed_mode(struct intel_connector *connector);
struct drm_display_mode *
intel_panel_vbt_fixed_mode(struct intel_connector *connector);
void intel_panel_set_pwm_level(const struct drm_connector_state *conn_state, u32 level);
u32 intel_panel_invert_pwm_level(struct intel_connector *connector, u32 level);
u32 intel_panel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
u32 intel_panel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
int intel_backlight_device_register(struct intel_connector *connector);
void intel_backlight_device_unregister(struct intel_connector *connector);
#else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
static inline int intel_backlight_device_register(struct intel_connector *connector)
{
return 0;
}
static inline void intel_backlight_device_unregister(struct intel_connector *connector)
{
}
#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
#endif /* __INTEL_PANEL_H__ */