// SPDX-License-Identifier: MIT /* * Copyright (C) 2019 Google, Inc. * * Authors: * Sean Paul <[email protected]> */ #include <linux/average.h> #include <linux/bitops.h> #include <linux/slab.h> #include <linux/workqueue.h> #include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h> #include <drm/drm_connector.h> #include <drm/drm_crtc.h> #include <drm/drm_device.h> #include <drm/drm_mode_config.h> #include <drm/drm_modeset_lock.h> #include <drm/drm_print.h> #include <drm/drm_self_refresh_helper.h> /** * DOC: overview * * This helper library provides an easy way for drivers to leverage the atomic * framework to implement panel self refresh (SR) support. Drivers are * responsible for initializing and cleaning up the SR helpers on load/unload * (see &drm_self_refresh_helper_init/&drm_self_refresh_helper_cleanup). * The connector is responsible for setting * &drm_connector_state.self_refresh_aware to true at runtime if it is SR-aware * (meaning it knows how to initiate self refresh on the panel). * * Once a crtc has enabled SR using &drm_self_refresh_helper_init, the * helpers will monitor activity and call back into the driver to enable/disable * SR as appropriate. The best way to think about this is that it's a DPMS * on/off request with &drm_crtc_state.self_refresh_active set in crtc state * that tells you to disable/enable SR on the panel instead of power-cycling it. * * During SR, drivers may choose to fully disable their crtc/encoder/bridge * hardware (in which case no driver changes are necessary), or they can inspect * &drm_crtc_state.self_refresh_active if they want to enter low power mode * without full disable (in case full disable/enable is too slow). * * SR will be deactivated if there are any atomic updates affecting the * pipe that is in SR mode. If a crtc is driving multiple connectors, all * connectors must be SR aware and all will enter/exit SR mode at the same time. * * If the crtc and connector are SR aware, but the panel connected does not * support it (or is otherwise unable to enter SR), the driver should fail * atomic_check when &drm_crtc_state.self_refresh_active is true. */ #define SELF_REFRESH_AVG_SEED_MS … DECLARE_EWMA(psr_time, 4, 4) struct drm_self_refresh_data { … }; static void drm_self_refresh_helper_entry_work(struct work_struct *work) { … } /** * drm_self_refresh_helper_update_avg_times - Updates a crtc's SR time averages * @state: the state which has just been applied to hardware * @commit_time_ms: the amount of time in ms that this commit took to complete * @new_self_refresh_mask: bitmask of crtc's that have self_refresh_active in * new state * * Called after &drm_mode_config_funcs.atomic_commit_tail, this function will * update the average entry/exit self refresh times on self refresh transitions. * These averages will be used when calculating how long to delay before * entering self refresh mode after activity. */ void drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state, unsigned int commit_time_ms, unsigned int new_self_refresh_mask) { … } EXPORT_SYMBOL(…); /** * drm_self_refresh_helper_alter_state - Alters the atomic state for SR exit * @state: the state currently being checked * * Called at the end of atomic check. This function checks the state for flags * incompatible with self refresh exit and changes them. This is a bit * disingenuous since userspace is expecting one thing and we're giving it * another. However in order to keep self refresh entirely hidden from * userspace, this is required. * * At the end, we queue up the self refresh entry work so we can enter PSR after * the desired delay. */ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) { … } EXPORT_SYMBOL(…); /** * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc * @crtc: the crtc which supports self refresh supported displays * * Returns zero if successful or -errno on failure */ int drm_self_refresh_helper_init(struct drm_crtc *crtc) { … } EXPORT_SYMBOL(…); /** * drm_self_refresh_helper_cleanup - Cleans up self refresh helpers for a crtc * @crtc: the crtc to cleanup */ void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc) { … } EXPORT_SYMBOL(…);
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