From 106b4a2a78b2a2f14885604891957b84bba502db Mon Sep 17 00:00:00 2001 From: Adrian Betschart Date: Fri, 11 Sep 2026 17:13:14 +0200 Subject: drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validation amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and uses the first encoding that validates. YCbCr 4:4:4 is listed before RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the "color format" property is left at AUTO, even though RGB fits the same link. That contradicts the documented AUTO behaviour for HDMI in enum drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when the bandwidth is not available or the mode is 4:2:0-only), which the amdgpu implementation of the property also describes. It also leaves the "Broadcast RGB" property without effect on such sinks, since the quantization range it selects only applies to RGB output. Try RGB first. The mask still holds every encoding the sink supports, so a mode that cannot carry RGB falls back exactly as before. For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI sink that advertised it. Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation") Suggested-by: Adolfo Rodrigues Assisted-by: Claude Code:claude-fable-5-1 Signed-off-by: Adrian Betschart Reviewed-by: Fangzhi Zuo Tested-by: Adolfo Rodrigues Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7) --- include/drm/drm_panel.h | 384 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 384 insertions(+) create mode 100644 include/drm/drm_panel.h (limited to 'include/drm/drm_panel.h') diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h new file mode 100644 index 000000000..b87323443 --- /dev/null +++ b/include/drm/drm_panel.h @@ -0,0 +1,384 @@ +/* + * Copyright (C) 2013, NVIDIA Corporation. All rights reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sub license, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the + * next paragraph) shall be included in all copies or substantial portions + * of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ + +#ifndef __DRM_PANEL_H__ +#define __DRM_PANEL_H__ + +#include +#include +#include +#include +#include + +struct backlight_device; +struct dentry; +struct device_node; +struct drm_connector; +struct drm_panel_follower; +struct drm_panel; +struct display_timing; + +enum drm_panel_orientation; + +/** + * struct drm_panel_funcs - perform operations on a given panel + * + * The .prepare() function is typically called before the display controller + * starts to transmit video data. Panel drivers can use this to turn the panel + * on and wait for it to become ready. If additional configuration is required + * (via a control bus such as I2C, SPI or DSI for example) this is a good time + * to do that. + * + * After the display controller has started transmitting video data, it's safe + * to call the .enable() function. This will typically enable the backlight to + * make the image on screen visible. Some panels require a certain amount of + * time or frames before the image is displayed. This function is responsible + * for taking this into account before enabling the backlight to avoid visual + * glitches. + * + * Before stopping video transmission from the display controller it can be + * necessary to turn off the panel to avoid visual glitches. This is done in + * the .disable() function. Analogously to .enable() this typically involves + * turning off the backlight and waiting for some time to make sure no image + * is visible on the panel. It is then safe for the display controller to + * cease transmission of video data. + * + * To save power when no video data is transmitted, a driver can power down + * the panel. This is the job of the .unprepare() function. + * + * Backlight can be handled automatically if configured using + * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver + * does not need to implement the functionality to enable/disable backlight. + */ +struct drm_panel_funcs { + /** + * @prepare: + * + * Turn on panel and perform set up. + * + * This function is optional. + */ + int (*prepare)(struct drm_panel *panel); + + /** + * @enable: + * + * Enable panel (turn on back light, etc.). + * + * This function is optional. + */ + int (*enable)(struct drm_panel *panel); + + /** + * @disable: + * + * Disable panel (turn off back light, etc.). + * + * This function is optional. + */ + int (*disable)(struct drm_panel *panel); + + /** + * @unprepare: + * + * Turn off panel. + * + * This function is optional. + */ + int (*unprepare)(struct drm_panel *panel); + + /** + * @get_modes: + * + * Add modes to the connector that the panel is attached to + * and returns the number of modes added. + * + * This function is mandatory. + */ + int (*get_modes)(struct drm_panel *panel, + struct drm_connector *connector); + + /** + * @get_orientation: + * + * Return the panel orientation set by device tree or EDID. + * + * This function is optional. + */ + enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel); + + /** + * @get_timings: + * + * Copy display timings into the provided array and return + * the number of display timings available. + * + * This function is optional. + */ + int (*get_timings)(struct drm_panel *panel, unsigned int num_timings, + struct display_timing *timings); + + /** + * @debugfs_init: + * + * Allows panels to create panels-specific debugfs files. + */ + void (*debugfs_init)(struct drm_panel *panel, struct dentry *root); +}; + +struct drm_panel_follower_funcs { + /** + * @panel_prepared: + * + * Called after the panel has been powered on. + */ + int (*panel_prepared)(struct drm_panel_follower *follower); + + /** + * @panel_unpreparing: + * + * Called before the panel is powered off. + */ + int (*panel_unpreparing)(struct drm_panel_follower *follower); + + /** + * @panel_enabled: + * + * Called after the panel and the backlight have been enabled. + */ + int (*panel_enabled)(struct drm_panel_follower *follower); + + /** + * @panel_disabling: + * + * Called before the panel and the backlight are disabled. + */ + int (*panel_disabling)(struct drm_panel_follower *follower); +}; + +struct drm_panel_follower { + /** + * @funcs: + * + * Dependent device callbacks; should be initted by the caller. + */ + const struct drm_panel_follower_funcs *funcs; + + /** + * @list + * + * Used for linking into panel's list; set by drm_panel_add_follower(). + */ + struct list_head list; + + /** + * @panel + * + * The panel we're dependent on; set by drm_panel_add_follower(). + */ + struct drm_panel *panel; +}; + +/** + * struct drm_panel - DRM panel object + */ +struct drm_panel { + /** + * @dev: + * + * Parent device of the panel. + */ + struct device *dev; + + /** + * @backlight: + * + * Backlight device, used to turn on backlight after the call + * to enable(), and to turn off backlight before the call to + * disable(). + * backlight is set by drm_panel_of_backlight() or + * drm_panel_dp_aux_backlight() and drivers shall not assign it. + */ + struct backlight_device *backlight; + + /** + * @funcs: + * + * Operations that can be performed on the panel. + */ + const struct drm_panel_funcs *funcs; + + /** + * @connector_type: + * + * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to + * initialise the drm_connector corresponding to the panel with the + * correct connector type. + */ + int connector_type; + + /** + * @list: + * + * Panel entry in registry. + */ + struct list_head list; + + /** + * @followers: + * + * A list of struct drm_panel_follower dependent on this panel. + */ + struct list_head followers; + + /** + * @follower_lock: + * + * Lock for followers list. + */ + struct mutex follower_lock; + + /** + * @prepare_prev_first: + * + * The previous controller should be prepared first, before the prepare + * for the panel is called. This is largely required for DSI panels + * where the DSI host controller should be initialised to LP-11 before + * the panel is powered up. + */ + bool prepare_prev_first; + + /** + * @prepared: + * + * If true then the panel has been prepared. + */ + bool prepared; + + /** + * @enabled: + * + * If true then the panel has been enabled. + */ + bool enabled; + + /** + * @container: Pointer to the private driver struct embedding this + * @struct drm_panel. + */ + void *container; + + /** + * @refcount: reference count of users referencing this panel. + */ + struct kref refcount; +}; + +void *__devm_drm_panel_alloc(struct device *dev, size_t size, size_t offset, + const struct drm_panel_funcs *funcs, + int connector_type); + +/** + * devm_drm_panel_alloc - Allocate and initialize a refcounted panel. + * + * @dev: struct device of the panel device + * @type: the type of the struct which contains struct &drm_panel + * @member: the name of the &drm_panel within @type + * @funcs: callbacks for this panel + * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to + * the panel interface + * + * The reference count of the returned panel is initialized to 1. This + * reference will be automatically dropped via devm (by calling + * drm_panel_put()) when @dev is removed. + * + * Returns: + * Pointer to container structure embedding the panel, ERR_PTR on failure. + */ +#define devm_drm_panel_alloc(dev, type, member, funcs, connector_type) \ + ((type *)__devm_drm_panel_alloc(dev, sizeof(type), \ + offsetof(type, member), funcs, \ + connector_type)) + +struct drm_panel *drm_panel_get(struct drm_panel *panel); +void drm_panel_put(struct drm_panel *panel); + +void drm_panel_add(struct drm_panel *panel); +void drm_panel_remove(struct drm_panel *panel); +int devm_drm_panel_add(struct device *dev, struct drm_panel *panel); + +void drm_panel_prepare(struct drm_panel *panel); +void drm_panel_unprepare(struct drm_panel *panel); + +void drm_panel_enable(struct drm_panel *panel); +void drm_panel_disable(struct drm_panel *panel); + +int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector); + +#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL) +struct drm_panel *of_drm_find_panel(const struct device_node *np); +#else +static inline struct drm_panel *of_drm_find_panel(const struct device_node *np) +{ + return ERR_PTR(-ENODEV); +} +#endif + +#if defined(CONFIG_DRM_PANEL) +bool drm_is_panel_follower(struct device *dev); +int drm_panel_add_follower(struct device *follower_dev, + struct drm_panel_follower *follower); +void drm_panel_remove_follower(struct drm_panel_follower *follower); +int devm_drm_panel_add_follower(struct device *follower_dev, + struct drm_panel_follower *follower); +#else +static inline bool drm_is_panel_follower(struct device *dev) +{ + return false; +} + +static inline int drm_panel_add_follower(struct device *follower_dev, + struct drm_panel_follower *follower) +{ + return -ENODEV; +} + +static inline void drm_panel_remove_follower(struct drm_panel_follower *follower) { } +static inline int devm_drm_panel_add_follower(struct device *follower_dev, + struct drm_panel_follower *follower) +{ + return -ENODEV; +} +#endif + +#if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \ + (IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE))) +int drm_panel_of_backlight(struct drm_panel *panel); +#else +static inline int drm_panel_of_backlight(struct drm_panel *panel) +{ + return 0; +} +#endif + +#endif -- cgit v1.3.1