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linux/include/drm/drm_self_refresh_helper.h

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drm: Add helpers to kick off self refresh mode in drivers This patch adds a new drm helper library to help drivers implement self refresh. Drivers choosing to use it will register crtcs and will receive callbacks when it's time to enter or exit self refresh mode. In its current form, it has a timer which will trigger after a driver-specified amount of inactivity. When the timer triggers, the helpers will submit a new atomic commit to shut the refreshing pipe off. On the next atomic commit, the drm core will revert the self refresh state and bring everything back up to be actively driven. From the driver's perspective, this works like a regular disable/enable cycle. The driver need only check the 'self_refresh_active' state in crtc_state. It should initiate self refresh mode on the panel and enter an off or low-power state. Changes in v2: - s/psr/self_refresh/ (Daniel) - integrated the psr exit into the commit that wakes it up (Jose/Daniel) - made the psr state per-crtc (Jose/Daniel) Changes in v3: - Remove the self_refresh_(active|changed) from connector state (Daniel) - Simplify loop in drm_self_refresh_helper_alter_state (Daniel) - Improve self_refresh_aware comment (Daniel) - s/self_refresh_state/self_refresh_data/ (Daniel) Changes in v4: - Move docbook location below panel (Daniel) - Improve docbook with references and more detailed explanation (Daniel) - Instead of register/unregister, use init/cleanup (Daniel) Changes in v5: - Resolved conflict in drm_atomic_helper.c #include block - Resolved conflict in rst with HDCP helper docs Changes in v6: - Fix include ordering, clean up forward declarations (Sam) Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190228210939.83386-2-sean@poorly.run Link to v2: https://patchwork.freedesktop.org/patch/msgid/20190326204509.96515-1-sean@poorly.run Link to v3: https://patchwork.freedesktop.org/patch/msgid/20190502194956.218441-6-sean@poorly.run Link to v4: https://patchwork.freedesktop.org/patch/msgid/20190508160920.144739-6-sean@poorly.run Link to v5: https://patchwork.freedesktop.org/patch/msgid/20190611160844.257498-6-sean@poorly.run Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Jose Souza <jose.souza@intel.com> Cc: Zain Wang <wzz@rock-chips.com> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Sam Ravnborg <sam@ravnborg.org> Tested-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190612145026.191846-1-sean@poorly.run
2019-06-12 22:50:19 +08:00
// SPDX-License-Identifier: MIT
/*
* Copyright (C) 2019 Google, Inc.
*
* Authors:
* Sean Paul <seanpaul@chromium.org>
*/
#ifndef DRM_SELF_REFRESH_HELPER_H_
#define DRM_SELF_REFRESH_HELPER_H_
struct drm_atomic_state;
struct drm_crtc;
void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state);
drm: Measure Self Refresh Entry/Exit times to avoid thrashing Currently the self refresh idle timer is a const set by the crtc. This is fine if the self refresh entry/exit times are well-known for all panels used on that crtc. However panels and workloads can vary quite a bit, and a timeout which works well for one doesn't work well for another. In the extreme, if the timeout is too short we could get in a situation where the self refresh exits are taking so long we queue up a self refresh entry before the exit commit is even finished. This patch changes the idle timeout to a moving average of the entry times + a moving average of exit times + the crtc constant. This patch was tested on rockchip, with a kevin CrOS panel the idle delay averages out to about ~235ms (35 entry + 100 exit + 100 const). On the same board, the bob panel idle delay lands around ~340ms (90 entry + 150 exit + 100 const). WRT the dedicated mutex in self_refresh_data, it would be nice if we could rely on drm_crtc.mutex to protect the average times, but there are a few reasons why a separate lock is a better choice: - We can't rely on drm_crtc.mutex being held if we're doing a nonblocking commit - We can't grab drm_crtc.mutex since drm_modeset_lock() doesn't tell us whether the lock was already held in the acquire context (it eats -EALREADY), so we can't tell if we should drop it or not - We don't need such a heavy-handed lock for what we're trying to do, commit ordering doesn't matter, so a point-of-use lock will be less contentious Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190917200443.64481-2-sean@poorly.run Link: https://patchwork.freedesktop.org/patch/msgid/20190918200734.149876-2-sean@poorly.run Changes in v2: - Migrate locking explanation from comment to commit msg (Daniel) - Turf constant entry delay and multiply the avg times by 2 (Daniel)
2019-09-19 04:07:29 +08:00
void drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state,
drm/atomic: fix self-refresh helpers crtc state dereference drm_self_refresh_helper_update_avg_times() was incorrectly accessing the new incoming state after drm_atomic_helper_commit_hw_done(). But this state might have already been superceeded by an !nonblock atomic update resulting in dereferencing an already free'd crtc_state. TODO I *think* this will more or less do the right thing.. althought I'm not 100% sure if, for example, we enter psr in a nonblock commit, and then leave psr in a !nonblock commit that overtakes the completion of the nonblock commit. Not sure if this sort of scenario can happen in practice. But not crashing is better than crashing, so I guess we should either take this patch or rever the self-refresh helpers until Sean can figure out a better solution. Fixes: d4da4e33341c ("drm: Measure Self Refresh Entry/Exit times to avoid thrashing") Cc: Sean Paul <seanpaul@chromium.org> Signed-off-by: Rob Clark <robdclark@chromium.org> [seanpaul fixed up some checkpatch warns] Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20191104173737.142558-1-robdclark@gmail.com
2019-11-05 01:37:36 +08:00
unsigned int commit_time_ms,
unsigned int new_self_refresh_mask);
drm: Add helpers to kick off self refresh mode in drivers This patch adds a new drm helper library to help drivers implement self refresh. Drivers choosing to use it will register crtcs and will receive callbacks when it's time to enter or exit self refresh mode. In its current form, it has a timer which will trigger after a driver-specified amount of inactivity. When the timer triggers, the helpers will submit a new atomic commit to shut the refreshing pipe off. On the next atomic commit, the drm core will revert the self refresh state and bring everything back up to be actively driven. From the driver's perspective, this works like a regular disable/enable cycle. The driver need only check the 'self_refresh_active' state in crtc_state. It should initiate self refresh mode on the panel and enter an off or low-power state. Changes in v2: - s/psr/self_refresh/ (Daniel) - integrated the psr exit into the commit that wakes it up (Jose/Daniel) - made the psr state per-crtc (Jose/Daniel) Changes in v3: - Remove the self_refresh_(active|changed) from connector state (Daniel) - Simplify loop in drm_self_refresh_helper_alter_state (Daniel) - Improve self_refresh_aware comment (Daniel) - s/self_refresh_state/self_refresh_data/ (Daniel) Changes in v4: - Move docbook location below panel (Daniel) - Improve docbook with references and more detailed explanation (Daniel) - Instead of register/unregister, use init/cleanup (Daniel) Changes in v5: - Resolved conflict in drm_atomic_helper.c #include block - Resolved conflict in rst with HDCP helper docs Changes in v6: - Fix include ordering, clean up forward declarations (Sam) Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190228210939.83386-2-sean@poorly.run Link to v2: https://patchwork.freedesktop.org/patch/msgid/20190326204509.96515-1-sean@poorly.run Link to v3: https://patchwork.freedesktop.org/patch/msgid/20190502194956.218441-6-sean@poorly.run Link to v4: https://patchwork.freedesktop.org/patch/msgid/20190508160920.144739-6-sean@poorly.run Link to v5: https://patchwork.freedesktop.org/patch/msgid/20190611160844.257498-6-sean@poorly.run Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Jose Souza <jose.souza@intel.com> Cc: Zain Wang <wzz@rock-chips.com> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Sam Ravnborg <sam@ravnborg.org> Tested-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190612145026.191846-1-sean@poorly.run
2019-06-12 22:50:19 +08:00
drm: Measure Self Refresh Entry/Exit times to avoid thrashing Currently the self refresh idle timer is a const set by the crtc. This is fine if the self refresh entry/exit times are well-known for all panels used on that crtc. However panels and workloads can vary quite a bit, and a timeout which works well for one doesn't work well for another. In the extreme, if the timeout is too short we could get in a situation where the self refresh exits are taking so long we queue up a self refresh entry before the exit commit is even finished. This patch changes the idle timeout to a moving average of the entry times + a moving average of exit times + the crtc constant. This patch was tested on rockchip, with a kevin CrOS panel the idle delay averages out to about ~235ms (35 entry + 100 exit + 100 const). On the same board, the bob panel idle delay lands around ~340ms (90 entry + 150 exit + 100 const). WRT the dedicated mutex in self_refresh_data, it would be nice if we could rely on drm_crtc.mutex to protect the average times, but there are a few reasons why a separate lock is a better choice: - We can't rely on drm_crtc.mutex being held if we're doing a nonblocking commit - We can't grab drm_crtc.mutex since drm_modeset_lock() doesn't tell us whether the lock was already held in the acquire context (it eats -EALREADY), so we can't tell if we should drop it or not - We don't need such a heavy-handed lock for what we're trying to do, commit ordering doesn't matter, so a point-of-use lock will be less contentious Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190917200443.64481-2-sean@poorly.run Link: https://patchwork.freedesktop.org/patch/msgid/20190918200734.149876-2-sean@poorly.run Changes in v2: - Migrate locking explanation from comment to commit msg (Daniel) - Turf constant entry delay and multiply the avg times by 2 (Daniel)
2019-09-19 04:07:29 +08:00
int drm_self_refresh_helper_init(struct drm_crtc *crtc);
drm: Add helpers to kick off self refresh mode in drivers This patch adds a new drm helper library to help drivers implement self refresh. Drivers choosing to use it will register crtcs and will receive callbacks when it's time to enter or exit self refresh mode. In its current form, it has a timer which will trigger after a driver-specified amount of inactivity. When the timer triggers, the helpers will submit a new atomic commit to shut the refreshing pipe off. On the next atomic commit, the drm core will revert the self refresh state and bring everything back up to be actively driven. From the driver's perspective, this works like a regular disable/enable cycle. The driver need only check the 'self_refresh_active' state in crtc_state. It should initiate self refresh mode on the panel and enter an off or low-power state. Changes in v2: - s/psr/self_refresh/ (Daniel) - integrated the psr exit into the commit that wakes it up (Jose/Daniel) - made the psr state per-crtc (Jose/Daniel) Changes in v3: - Remove the self_refresh_(active|changed) from connector state (Daniel) - Simplify loop in drm_self_refresh_helper_alter_state (Daniel) - Improve self_refresh_aware comment (Daniel) - s/self_refresh_state/self_refresh_data/ (Daniel) Changes in v4: - Move docbook location below panel (Daniel) - Improve docbook with references and more detailed explanation (Daniel) - Instead of register/unregister, use init/cleanup (Daniel) Changes in v5: - Resolved conflict in drm_atomic_helper.c #include block - Resolved conflict in rst with HDCP helper docs Changes in v6: - Fix include ordering, clean up forward declarations (Sam) Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190228210939.83386-2-sean@poorly.run Link to v2: https://patchwork.freedesktop.org/patch/msgid/20190326204509.96515-1-sean@poorly.run Link to v3: https://patchwork.freedesktop.org/patch/msgid/20190502194956.218441-6-sean@poorly.run Link to v4: https://patchwork.freedesktop.org/patch/msgid/20190508160920.144739-6-sean@poorly.run Link to v5: https://patchwork.freedesktop.org/patch/msgid/20190611160844.257498-6-sean@poorly.run Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Jose Souza <jose.souza@intel.com> Cc: Zain Wang <wzz@rock-chips.com> Cc: Tomasz Figa <tfiga@chromium.org> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Sam Ravnborg <sam@ravnborg.org> Tested-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190612145026.191846-1-sean@poorly.run
2019-06-12 22:50:19 +08:00
void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc);
#endif
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