* [PATCH v2 2/3] drm: Measure Self Refresh Entry/Exit times to avoid thrashing [not found] <20190918200734.149876-1-sean@poorly.run> @ 2019-09-18 20:07 ` Sean Paul 2019-09-19 14:14 ` Sean Paul 0 siblings, 1 reply; 4+ messages in thread From: Sean Paul @ 2019-09-18 20:07 UTC (permalink / raw) To: dri-devel Cc: heiko, linux-rockchip, Maxime Ripard, Daniel Vetter, Maarten Lankhorst, Sandy Huang, linux-kernel, David Airlie, Sean Paul, daniel, jekarl, Sean Paul, linux-arm-kernel From: Sean Paul <seanpaul@chromium.org> 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 Changes in v2: - Migrate locking explanation from comment to commit msg (Daniel) - Turf constant entry delay and multiply the avg times by 2 (Daniel) --- drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++ drivers/gpu/drm/drm_self_refresh_helper.c | 72 +++++++++++++++++++-- drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 +- include/drm/drm_self_refresh_helper.h | 6 +- 4 files changed, 90 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 9d7e4da6c292..3f13fa9a9e24 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -26,6 +26,7 @@ */ #include <linux/dma-fence.h> +#include <linux/ktime.h> #include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h> @@ -1570,9 +1571,23 @@ static void commit_tail(struct drm_atomic_state *old_state) { struct drm_device *dev = old_state->dev; const struct drm_mode_config_helper_funcs *funcs; + ktime_t start; + s64 commit_time_ms; funcs = dev->mode_config.helper_private; + /* + * We're measuring the _entire_ commit, so the time will vary depending + * on how many fences and objects are involved. For the purposes of self + * refresh, this is desirable since it'll give us an idea of how + * congested things are. This will inform our decision on how often we + * should enter self refresh after idle. + * + * These times will be averaged out in the self refresh helpers to avoid + * overreacting over one outlier frame + */ + start = ktime_get(); + drm_atomic_helper_wait_for_fences(dev, old_state, false); drm_atomic_helper_wait_for_dependencies(old_state); @@ -1582,6 +1597,11 @@ static void commit_tail(struct drm_atomic_state *old_state) else drm_atomic_helper_commit_tail(old_state); + commit_time_ms = ktime_ms_delta(ktime_get(), start); + if (commit_time_ms > 0) + drm_self_refresh_helper_update_avg_times(old_state, + (unsigned long)commit_time_ms); + drm_atomic_helper_commit_cleanup_done(old_state); drm_atomic_state_put(old_state); diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c index 9095cebf2147..68f4765a5896 100644 --- a/drivers/gpu/drm/drm_self_refresh_helper.c +++ b/drivers/gpu/drm/drm_self_refresh_helper.c @@ -5,6 +5,7 @@ * Authors: * Sean Paul <seanpaul@chromium.org> */ +#include <linux/average.h> #include <linux/bitops.h> #include <linux/slab.h> #include <linux/workqueue.h> @@ -50,10 +51,17 @@ * atomic_check when &drm_crtc_state.self_refresh_active is true. */ +#define SELF_REFRESH_AVG_SEED_MS 200 + +DECLARE_EWMA(psr_time, 4, 4) + struct drm_self_refresh_data { struct drm_crtc *crtc; struct delayed_work entry_work; - unsigned int entry_delay_ms; + + struct mutex avg_mutex; + struct ewma_psr_time entry_avg_ms; + struct ewma_psr_time exit_avg_ms; }; static void drm_self_refresh_helper_entry_work(struct work_struct *work) @@ -121,6 +129,44 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) drm_modeset_acquire_fini(&ctx); } +/** + * 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 + * + * 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) +{ + struct drm_crtc *crtc; + struct drm_crtc_state *old_crtc_state, *new_crtc_state; + int i; + + for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, + new_crtc_state, i) { + struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; + struct ewma_psr_time *time; + + if (old_crtc_state->self_refresh_active == + new_crtc_state->self_refresh_active) + continue; + + if (new_crtc_state->self_refresh_active) + time = &sr_data->entry_avg_ms; + else + time = &sr_data->exit_avg_ms; + + mutex_lock(&sr_data->avg_mutex); + ewma_psr_time_add(time, commit_time_ms); + mutex_unlock(&sr_data->avg_mutex); + } +} +EXPORT_SYMBOL(drm_self_refresh_helper_update_avg_times); + /** * drm_self_refresh_helper_alter_state - Alters the atomic state for SR exit * @state: the state currently being checked @@ -152,6 +198,7 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) for_each_new_crtc_in_state(state, crtc, crtc_state, i) { struct drm_self_refresh_data *sr_data; + unsigned int delay; /* Don't trigger the entry timer when we're already in SR */ if (crtc_state->self_refresh_active) @@ -161,8 +208,13 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) if (!sr_data) continue; + mutex_lock(&sr_data->avg_mutex); + delay = (ewma_psr_time_read(&sr_data->entry_avg_ms) + + ewma_psr_time_read(&sr_data->exit_avg_ms)) * 2; + mutex_unlock(&sr_data->avg_mutex); + mod_delayed_work(system_wq, &sr_data->entry_work, - msecs_to_jiffies(sr_data->entry_delay_ms)); + msecs_to_jiffies(delay)); } } EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); @@ -170,12 +222,10 @@ EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); /** * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc * @crtc: the crtc which supports self refresh supported displays - * @entry_delay_ms: amount of inactivity to wait before entering self refresh * * Returns zero if successful or -errno on failure */ -int drm_self_refresh_helper_init(struct drm_crtc *crtc, - unsigned int entry_delay_ms) +int drm_self_refresh_helper_init(struct drm_crtc *crtc) { struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; @@ -189,8 +239,18 @@ int drm_self_refresh_helper_init(struct drm_crtc *crtc, INIT_DELAYED_WORK(&sr_data->entry_work, drm_self_refresh_helper_entry_work); - sr_data->entry_delay_ms = entry_delay_ms; sr_data->crtc = crtc; + mutex_init(&sr_data->avg_mutex); + ewma_psr_time_init(&sr_data->entry_avg_ms); + ewma_psr_time_init(&sr_data->exit_avg_ms); + + /* + * Seed the averages so they're non-zero (and sufficiently large + * for even poorly performing panels). As time goes on, this will be + * averaged out and the values will trend to their true value. + */ + ewma_psr_time_add(&sr_data->entry_avg_ms, SELF_REFRESH_AVG_SEED_MS); + ewma_psr_time_add(&sr_data->exit_avg_ms, SELF_REFRESH_AVG_SEED_MS); crtc->self_refresh_data = sr_data; return 0; diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c index 2f821c58007c..613404f86668 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c @@ -39,8 +39,6 @@ #include "rockchip_drm_vop.h" #include "rockchip_rgb.h" -#define VOP_SELF_REFRESH_ENTRY_DELAY_MS 100 - #define VOP_WIN_SET(vop, win, name, v) \ vop_reg_set(vop, &win->phy->name, win->base, ~0, v, #name) #define VOP_SCL_SET(vop, win, name, v) \ @@ -1563,8 +1561,7 @@ static int vop_create_crtc(struct vop *vop) init_completion(&vop->line_flag_completion); crtc->port = port; - ret = drm_self_refresh_helper_init(crtc, - VOP_SELF_REFRESH_ENTRY_DELAY_MS); + ret = drm_self_refresh_helper_init(crtc); if (ret) DRM_DEV_DEBUG_KMS(vop->dev, "Failed to init %s with SR helpers %d, ignoring\n", diff --git a/include/drm/drm_self_refresh_helper.h b/include/drm/drm_self_refresh_helper.h index 397a583ccca7..5b79d253fb46 100644 --- a/include/drm/drm_self_refresh_helper.h +++ b/include/drm/drm_self_refresh_helper.h @@ -12,9 +12,9 @@ struct drm_atomic_state; struct drm_crtc; void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state); +void drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state, + unsigned int commit_time_ms); -int drm_self_refresh_helper_init(struct drm_crtc *crtc, - unsigned int entry_delay_ms); - +int drm_self_refresh_helper_init(struct drm_crtc *crtc); void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc); #endif -- Sean Paul, Software Engineer, Google / Chromium OS _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 2/3] drm: Measure Self Refresh Entry/Exit times to avoid thrashing 2019-09-18 20:07 ` [PATCH v2 2/3] drm: Measure Self Refresh Entry/Exit times to avoid thrashing Sean Paul @ 2019-09-19 14:14 ` Sean Paul 2019-10-30 16:59 ` Enric Balletbo Serra 0 siblings, 1 reply; 4+ messages in thread From: Sean Paul @ 2019-09-19 14:14 UTC (permalink / raw) To: dri-devel Cc: heiko, David Airlie, Daniel Vetter, Maarten Lankhorst, Sandy Huang, linux-kernel, linux-rockchip, Sean Paul, daniel, jekarl, Sean Paul, linux-arm-kernel On Wed, Sep 18, 2019 at 04:07:29PM -0400, Sean Paul wrote: > From: Sean Paul <seanpaul@chromium.org> > > 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> Pushed the first 2 to drm-misc-next-fixes to fix the gru-bob regression. I'll fix up the 3rd patch separately. Thank you for the reviews! Sean > Signed-off-by: Sean Paul <seanpaul@chromium.org> > Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190917200443.64481-2-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) > --- > drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++ > drivers/gpu/drm/drm_self_refresh_helper.c | 72 +++++++++++++++++++-- > drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 +- > include/drm/drm_self_refresh_helper.h | 6 +- > 4 files changed, 90 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index 9d7e4da6c292..3f13fa9a9e24 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -26,6 +26,7 @@ > */ > > #include <linux/dma-fence.h> > +#include <linux/ktime.h> > > #include <drm/drm_atomic.h> > #include <drm/drm_atomic_helper.h> > @@ -1570,9 +1571,23 @@ static void commit_tail(struct drm_atomic_state *old_state) > { > struct drm_device *dev = old_state->dev; > const struct drm_mode_config_helper_funcs *funcs; > + ktime_t start; > + s64 commit_time_ms; > > funcs = dev->mode_config.helper_private; > > + /* > + * We're measuring the _entire_ commit, so the time will vary depending > + * on how many fences and objects are involved. For the purposes of self > + * refresh, this is desirable since it'll give us an idea of how > + * congested things are. This will inform our decision on how often we > + * should enter self refresh after idle. > + * > + * These times will be averaged out in the self refresh helpers to avoid > + * overreacting over one outlier frame > + */ > + start = ktime_get(); > + > drm_atomic_helper_wait_for_fences(dev, old_state, false); > > drm_atomic_helper_wait_for_dependencies(old_state); > @@ -1582,6 +1597,11 @@ static void commit_tail(struct drm_atomic_state *old_state) > else > drm_atomic_helper_commit_tail(old_state); > > + commit_time_ms = ktime_ms_delta(ktime_get(), start); > + if (commit_time_ms > 0) > + drm_self_refresh_helper_update_avg_times(old_state, > + (unsigned long)commit_time_ms); > + > drm_atomic_helper_commit_cleanup_done(old_state); > > drm_atomic_state_put(old_state); > diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c > index 9095cebf2147..68f4765a5896 100644 > --- a/drivers/gpu/drm/drm_self_refresh_helper.c > +++ b/drivers/gpu/drm/drm_self_refresh_helper.c > @@ -5,6 +5,7 @@ > * Authors: > * Sean Paul <seanpaul@chromium.org> > */ > +#include <linux/average.h> > #include <linux/bitops.h> > #include <linux/slab.h> > #include <linux/workqueue.h> > @@ -50,10 +51,17 @@ > * atomic_check when &drm_crtc_state.self_refresh_active is true. > */ > > +#define SELF_REFRESH_AVG_SEED_MS 200 > + > +DECLARE_EWMA(psr_time, 4, 4) > + > struct drm_self_refresh_data { > struct drm_crtc *crtc; > struct delayed_work entry_work; > - unsigned int entry_delay_ms; > + > + struct mutex avg_mutex; > + struct ewma_psr_time entry_avg_ms; > + struct ewma_psr_time exit_avg_ms; > }; > > static void drm_self_refresh_helper_entry_work(struct work_struct *work) > @@ -121,6 +129,44 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) > drm_modeset_acquire_fini(&ctx); > } > > +/** > + * 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 > + * > + * 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) > +{ > + struct drm_crtc *crtc; > + struct drm_crtc_state *old_crtc_state, *new_crtc_state; > + int i; > + > + for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, > + new_crtc_state, i) { > + struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > + struct ewma_psr_time *time; > + > + if (old_crtc_state->self_refresh_active == > + new_crtc_state->self_refresh_active) > + continue; > + > + if (new_crtc_state->self_refresh_active) > + time = &sr_data->entry_avg_ms; > + else > + time = &sr_data->exit_avg_ms; > + > + mutex_lock(&sr_data->avg_mutex); > + ewma_psr_time_add(time, commit_time_ms); > + mutex_unlock(&sr_data->avg_mutex); > + } > +} > +EXPORT_SYMBOL(drm_self_refresh_helper_update_avg_times); > + > /** > * drm_self_refresh_helper_alter_state - Alters the atomic state for SR exit > * @state: the state currently being checked > @@ -152,6 +198,7 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > > for_each_new_crtc_in_state(state, crtc, crtc_state, i) { > struct drm_self_refresh_data *sr_data; > + unsigned int delay; > > /* Don't trigger the entry timer when we're already in SR */ > if (crtc_state->self_refresh_active) > @@ -161,8 +208,13 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > if (!sr_data) > continue; > > + mutex_lock(&sr_data->avg_mutex); > + delay = (ewma_psr_time_read(&sr_data->entry_avg_ms) + > + ewma_psr_time_read(&sr_data->exit_avg_ms)) * 2; > + mutex_unlock(&sr_data->avg_mutex); > + > mod_delayed_work(system_wq, &sr_data->entry_work, > - msecs_to_jiffies(sr_data->entry_delay_ms)); > + msecs_to_jiffies(delay)); > } > } > EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > @@ -170,12 +222,10 @@ EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > /** > * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc > * @crtc: the crtc which supports self refresh supported displays > - * @entry_delay_ms: amount of inactivity to wait before entering self refresh > * > * Returns zero if successful or -errno on failure > */ > -int drm_self_refresh_helper_init(struct drm_crtc *crtc, > - unsigned int entry_delay_ms) > +int drm_self_refresh_helper_init(struct drm_crtc *crtc) > { > struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > > @@ -189,8 +239,18 @@ int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > INIT_DELAYED_WORK(&sr_data->entry_work, > drm_self_refresh_helper_entry_work); > - sr_data->entry_delay_ms = entry_delay_ms; > sr_data->crtc = crtc; > + mutex_init(&sr_data->avg_mutex); > + ewma_psr_time_init(&sr_data->entry_avg_ms); > + ewma_psr_time_init(&sr_data->exit_avg_ms); > + > + /* > + * Seed the averages so they're non-zero (and sufficiently large > + * for even poorly performing panels). As time goes on, this will be > + * averaged out and the values will trend to their true value. > + */ > + ewma_psr_time_add(&sr_data->entry_avg_ms, SELF_REFRESH_AVG_SEED_MS); > + ewma_psr_time_add(&sr_data->exit_avg_ms, SELF_REFRESH_AVG_SEED_MS); > > crtc->self_refresh_data = sr_data; > return 0; > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > index 2f821c58007c..613404f86668 100644 > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > @@ -39,8 +39,6 @@ > #include "rockchip_drm_vop.h" > #include "rockchip_rgb.h" > > -#define VOP_SELF_REFRESH_ENTRY_DELAY_MS 100 > - > #define VOP_WIN_SET(vop, win, name, v) \ > vop_reg_set(vop, &win->phy->name, win->base, ~0, v, #name) > #define VOP_SCL_SET(vop, win, name, v) \ > @@ -1563,8 +1561,7 @@ static int vop_create_crtc(struct vop *vop) > init_completion(&vop->line_flag_completion); > crtc->port = port; > > - ret = drm_self_refresh_helper_init(crtc, > - VOP_SELF_REFRESH_ENTRY_DELAY_MS); > + ret = drm_self_refresh_helper_init(crtc); > if (ret) > DRM_DEV_DEBUG_KMS(vop->dev, > "Failed to init %s with SR helpers %d, ignoring\n", > diff --git a/include/drm/drm_self_refresh_helper.h b/include/drm/drm_self_refresh_helper.h > index 397a583ccca7..5b79d253fb46 100644 > --- a/include/drm/drm_self_refresh_helper.h > +++ b/include/drm/drm_self_refresh_helper.h > @@ -12,9 +12,9 @@ struct drm_atomic_state; > struct drm_crtc; > > void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state); > +void drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state, > + unsigned int commit_time_ms); > > -int drm_self_refresh_helper_init(struct drm_crtc *crtc, > - unsigned int entry_delay_ms); > - > +int drm_self_refresh_helper_init(struct drm_crtc *crtc); > void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc); > #endif > -- > Sean Paul, Software Engineer, Google / Chromium OS > -- Sean Paul, Software Engineer, Google / Chromium OS _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 2/3] drm: Measure Self Refresh Entry/Exit times to avoid thrashing 2019-09-19 14:14 ` Sean Paul @ 2019-10-30 16:59 ` Enric Balletbo Serra 2019-11-04 17:26 ` Enric Balletbo Serra 0 siblings, 1 reply; 4+ messages in thread From: Enric Balletbo Serra @ 2019-10-30 16:59 UTC (permalink / raw) To: Sean Paul Cc: David Airlie, Daniel Vetter, linux-kernel, dri-devel, open list:ARM/Rockchip SoC..., Sean Paul, jekarl, Linux ARM Hi Sean, Since 5.4-rc1 my Samsung Chromebook Plus (kevin) doesn't suspend/resume correctly, at least once every ten suspend/resume cycles the display doesn't turn on, and when this happens the kernel log message reports: [ 60.420230] PM: suspend exit [ 60.463866] rockchip-dp ff970000.edp: AUX CH cmd reply timeout! [ 60.971653] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 61.478668] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 61.985661] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 62.492644] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 62.999617] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 63.506595] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 64.013678] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 64.522856] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 60.463866] rockchip-dp ff970000.edp: AUX CH cmd reply timeout! [ 60.971653] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 61.478668] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 61.985661] rockchip-dp ff970000.edp: AUX CH enable timeout! [ 62.492644] rockchip-dp ff970000.edp: AUX CH enable timeout! ... Today I bisected the problem and pointed me to this commit. Reverting the commit fixes the issue, but from I quick look I don't see any obvious problem. I'll spend more time tomorrow looking at this but any idea will be welcome. Thanks, Enric Missatge de Sean Paul <sean@poorly.run> del dia dj., 19 de set. 2019 a les 16:14: > > On Wed, Sep 18, 2019 at 04:07:29PM -0400, Sean Paul wrote: > > From: Sean Paul <seanpaul@chromium.org> > > > > 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> > > Pushed the first 2 to drm-misc-next-fixes to fix the gru-bob regression. I'll > fix up the 3rd patch separately. > > Thank you for the reviews! > > Sean > > > Signed-off-by: Sean Paul <seanpaul@chromium.org> > > Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190917200443.64481-2-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) > > --- > > drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++ > > drivers/gpu/drm/drm_self_refresh_helper.c | 72 +++++++++++++++++++-- > > drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 +- > > include/drm/drm_self_refresh_helper.h | 6 +- > > 4 files changed, 90 insertions(+), 13 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index 9d7e4da6c292..3f13fa9a9e24 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -26,6 +26,7 @@ > > */ > > > > #include <linux/dma-fence.h> > > +#include <linux/ktime.h> > > > > #include <drm/drm_atomic.h> > > #include <drm/drm_atomic_helper.h> > > @@ -1570,9 +1571,23 @@ static void commit_tail(struct drm_atomic_state *old_state) > > { > > struct drm_device *dev = old_state->dev; > > const struct drm_mode_config_helper_funcs *funcs; > > + ktime_t start; > > + s64 commit_time_ms; > > > > funcs = dev->mode_config.helper_private; > > > > + /* > > + * We're measuring the _entire_ commit, so the time will vary depending > > + * on how many fences and objects are involved. For the purposes of self > > + * refresh, this is desirable since it'll give us an idea of how > > + * congested things are. This will inform our decision on how often we > > + * should enter self refresh after idle. > > + * > > + * These times will be averaged out in the self refresh helpers to avoid > > + * overreacting over one outlier frame > > + */ > > + start = ktime_get(); > > + > > drm_atomic_helper_wait_for_fences(dev, old_state, false); > > > > drm_atomic_helper_wait_for_dependencies(old_state); > > @@ -1582,6 +1597,11 @@ static void commit_tail(struct drm_atomic_state *old_state) > > else > > drm_atomic_helper_commit_tail(old_state); > > > > + commit_time_ms = ktime_ms_delta(ktime_get(), start); > > + if (commit_time_ms > 0) > > + drm_self_refresh_helper_update_avg_times(old_state, > > + (unsigned long)commit_time_ms); > > + > > drm_atomic_helper_commit_cleanup_done(old_state); > > > > drm_atomic_state_put(old_state); > > diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c > > index 9095cebf2147..68f4765a5896 100644 > > --- a/drivers/gpu/drm/drm_self_refresh_helper.c > > +++ b/drivers/gpu/drm/drm_self_refresh_helper.c > > @@ -5,6 +5,7 @@ > > * Authors: > > * Sean Paul <seanpaul@chromium.org> > > */ > > +#include <linux/average.h> > > #include <linux/bitops.h> > > #include <linux/slab.h> > > #include <linux/workqueue.h> > > @@ -50,10 +51,17 @@ > > * atomic_check when &drm_crtc_state.self_refresh_active is true. > > */ > > > > +#define SELF_REFRESH_AVG_SEED_MS 200 > > + > > +DECLARE_EWMA(psr_time, 4, 4) > > + > > struct drm_self_refresh_data { > > struct drm_crtc *crtc; > > struct delayed_work entry_work; > > - unsigned int entry_delay_ms; > > + > > + struct mutex avg_mutex; > > + struct ewma_psr_time entry_avg_ms; > > + struct ewma_psr_time exit_avg_ms; > > }; > > > > static void drm_self_refresh_helper_entry_work(struct work_struct *work) > > @@ -121,6 +129,44 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) > > drm_modeset_acquire_fini(&ctx); > > } > > > > +/** > > + * 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 > > + * > > + * 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) > > +{ > > + struct drm_crtc *crtc; > > + struct drm_crtc_state *old_crtc_state, *new_crtc_state; > > + int i; > > + > > + for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, > > + new_crtc_state, i) { > > + struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > > + struct ewma_psr_time *time; > > + > > + if (old_crtc_state->self_refresh_active == > > + new_crtc_state->self_refresh_active) > > + continue; > > + > > + if (new_crtc_state->self_refresh_active) > > + time = &sr_data->entry_avg_ms; > > + else > > + time = &sr_data->exit_avg_ms; > > + > > + mutex_lock(&sr_data->avg_mutex); > > + ewma_psr_time_add(time, commit_time_ms); > > + mutex_unlock(&sr_data->avg_mutex); > > + } > > +} > > +EXPORT_SYMBOL(drm_self_refresh_helper_update_avg_times); > > + > > /** > > * drm_self_refresh_helper_alter_state - Alters the atomic state for SR exit > > * @state: the state currently being checked > > @@ -152,6 +198,7 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > > > > for_each_new_crtc_in_state(state, crtc, crtc_state, i) { > > struct drm_self_refresh_data *sr_data; > > + unsigned int delay; > > > > /* Don't trigger the entry timer when we're already in SR */ > > if (crtc_state->self_refresh_active) > > @@ -161,8 +208,13 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > > if (!sr_data) > > continue; > > > > + mutex_lock(&sr_data->avg_mutex); > > + delay = (ewma_psr_time_read(&sr_data->entry_avg_ms) + > > + ewma_psr_time_read(&sr_data->exit_avg_ms)) * 2; > > + mutex_unlock(&sr_data->avg_mutex); > > + > > mod_delayed_work(system_wq, &sr_data->entry_work, > > - msecs_to_jiffies(sr_data->entry_delay_ms)); > > + msecs_to_jiffies(delay)); > > } > > } > > EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > > @@ -170,12 +222,10 @@ EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > > /** > > * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc > > * @crtc: the crtc which supports self refresh supported displays > > - * @entry_delay_ms: amount of inactivity to wait before entering self refresh > > * > > * Returns zero if successful or -errno on failure > > */ > > -int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > - unsigned int entry_delay_ms) > > +int drm_self_refresh_helper_init(struct drm_crtc *crtc) > > { > > struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > > > > @@ -189,8 +239,18 @@ int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > > > INIT_DELAYED_WORK(&sr_data->entry_work, > > drm_self_refresh_helper_entry_work); > > - sr_data->entry_delay_ms = entry_delay_ms; > > sr_data->crtc = crtc; > > + mutex_init(&sr_data->avg_mutex); > > + ewma_psr_time_init(&sr_data->entry_avg_ms); > > + ewma_psr_time_init(&sr_data->exit_avg_ms); > > + > > + /* > > + * Seed the averages so they're non-zero (and sufficiently large > > + * for even poorly performing panels). As time goes on, this will be > > + * averaged out and the values will trend to their true value. > > + */ > > + ewma_psr_time_add(&sr_data->entry_avg_ms, SELF_REFRESH_AVG_SEED_MS); > > + ewma_psr_time_add(&sr_data->exit_avg_ms, SELF_REFRESH_AVG_SEED_MS); > > > > crtc->self_refresh_data = sr_data; > > return 0; > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > > index 2f821c58007c..613404f86668 100644 > > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > > @@ -39,8 +39,6 @@ > > #include "rockchip_drm_vop.h" > > #include "rockchip_rgb.h" > > > > -#define VOP_SELF_REFRESH_ENTRY_DELAY_MS 100 > > - > > #define VOP_WIN_SET(vop, win, name, v) \ > > vop_reg_set(vop, &win->phy->name, win->base, ~0, v, #name) > > #define VOP_SCL_SET(vop, win, name, v) \ > > @@ -1563,8 +1561,7 @@ static int vop_create_crtc(struct vop *vop) > > init_completion(&vop->line_flag_completion); > > crtc->port = port; > > > > - ret = drm_self_refresh_helper_init(crtc, > > - VOP_SELF_REFRESH_ENTRY_DELAY_MS); > > + ret = drm_self_refresh_helper_init(crtc); > > if (ret) > > DRM_DEV_DEBUG_KMS(vop->dev, > > "Failed to init %s with SR helpers %d, ignoring\n", > > diff --git a/include/drm/drm_self_refresh_helper.h b/include/drm/drm_self_refresh_helper.h > > index 397a583ccca7..5b79d253fb46 100644 > > --- a/include/drm/drm_self_refresh_helper.h > > +++ b/include/drm/drm_self_refresh_helper.h > > @@ -12,9 +12,9 @@ struct drm_atomic_state; > > struct drm_crtc; > > > > void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state); > > +void drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state, > > + unsigned int commit_time_ms); > > > > -int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > - unsigned int entry_delay_ms); > > - > > +int drm_self_refresh_helper_init(struct drm_crtc *crtc); > > void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc); > > #endif > > -- > > Sean Paul, Software Engineer, Google / Chromium OS > > > > -- > Sean Paul, Software Engineer, Google / Chromium OS > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 2/3] drm: Measure Self Refresh Entry/Exit times to avoid thrashing 2019-10-30 16:59 ` Enric Balletbo Serra @ 2019-11-04 17:26 ` Enric Balletbo Serra 0 siblings, 0 replies; 4+ messages in thread From: Enric Balletbo Serra @ 2019-11-04 17:26 UTC (permalink / raw) To: Sean Paul Cc: David Airlie, Daniel Vetter, linux-kernel, dri-devel, open list:ARM/Rockchip SoC..., Sean Paul, jekarl, Linux ARM Missatge de Enric Balletbo Serra <eballetbo@gmail.com> del dia dc., 30 d’oct. 2019 a les 17:59: > > Hi Sean, > > Since 5.4-rc1 my Samsung Chromebook Plus (kevin) doesn't > suspend/resume correctly, at least once every ten suspend/resume > cycles the display doesn't turn on, and when this happens the kernel > log message reports: > > [ 60.420230] PM: suspend exit > [ 60.463866] rockchip-dp ff970000.edp: AUX CH cmd reply timeout! > [ 60.971653] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 61.478668] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 61.985661] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 62.492644] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 62.999617] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 63.506595] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 64.013678] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 64.522856] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 60.463866] rockchip-dp ff970000.edp: AUX CH cmd reply timeout! > [ 60.971653] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 61.478668] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 61.985661] rockchip-dp ff970000.edp: AUX CH enable timeout! > [ 62.492644] rockchip-dp ff970000.edp: AUX CH enable timeout! > ... > > Today I bisected the problem and pointed me to this commit. Reverting > the commit fixes the issue, but from I quick look I don't see any > obvious problem. I'll spend more time tomorrow looking at this but any > idea will be welcome. > Update for the record. After looking a bit more I don't think this patch is problematic. I think the problem was already there but after this patch is easier to reproduce just because the PSR entry code work is delayed a bit (before was called every 100ms). I think the problem is more related with the current enable/disable path when panel is in SR mode or not after a suspend/resume. Anyway, I will continue the discussion on another thread when I find the root cause. Thanks, Enric > Thanks, > Enric > > Missatge de Sean Paul <sean@poorly.run> del dia dj., 19 de set. 2019 a > les 16:14: > > > > On Wed, Sep 18, 2019 at 04:07:29PM -0400, Sean Paul wrote: > > > From: Sean Paul <seanpaul@chromium.org> > > > > > > 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> > > > > Pushed the first 2 to drm-misc-next-fixes to fix the gru-bob regression. I'll > > fix up the 3rd patch separately. > > > > Thank you for the reviews! > > > > Sean > > > > > Signed-off-by: Sean Paul <seanpaul@chromium.org> > > > Link to v1: https://patchwork.freedesktop.org/patch/msgid/20190917200443.64481-2-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) > > > --- > > > drivers/gpu/drm/drm_atomic_helper.c | 20 ++++++ > > > drivers/gpu/drm/drm_self_refresh_helper.c | 72 +++++++++++++++++++-- > > > drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 5 +- > > > include/drm/drm_self_refresh_helper.h | 6 +- > > > 4 files changed, 90 insertions(+), 13 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > > index 9d7e4da6c292..3f13fa9a9e24 100644 > > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > > @@ -26,6 +26,7 @@ > > > */ > > > > > > #include <linux/dma-fence.h> > > > +#include <linux/ktime.h> > > > > > > #include <drm/drm_atomic.h> > > > #include <drm/drm_atomic_helper.h> > > > @@ -1570,9 +1571,23 @@ static void commit_tail(struct drm_atomic_state *old_state) > > > { > > > struct drm_device *dev = old_state->dev; > > > const struct drm_mode_config_helper_funcs *funcs; > > > + ktime_t start; > > > + s64 commit_time_ms; > > > > > > funcs = dev->mode_config.helper_private; > > > > > > + /* > > > + * We're measuring the _entire_ commit, so the time will vary depending > > > + * on how many fences and objects are involved. For the purposes of self > > > + * refresh, this is desirable since it'll give us an idea of how > > > + * congested things are. This will inform our decision on how often we > > > + * should enter self refresh after idle. > > > + * > > > + * These times will be averaged out in the self refresh helpers to avoid > > > + * overreacting over one outlier frame > > > + */ > > > + start = ktime_get(); > > > + > > > drm_atomic_helper_wait_for_fences(dev, old_state, false); > > > > > > drm_atomic_helper_wait_for_dependencies(old_state); > > > @@ -1582,6 +1597,11 @@ static void commit_tail(struct drm_atomic_state *old_state) > > > else > > > drm_atomic_helper_commit_tail(old_state); > > > > > > + commit_time_ms = ktime_ms_delta(ktime_get(), start); > > > + if (commit_time_ms > 0) > > > + drm_self_refresh_helper_update_avg_times(old_state, > > > + (unsigned long)commit_time_ms); > > > + > > > drm_atomic_helper_commit_cleanup_done(old_state); > > > > > > drm_atomic_state_put(old_state); > > > diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c > > > index 9095cebf2147..68f4765a5896 100644 > > > --- a/drivers/gpu/drm/drm_self_refresh_helper.c > > > +++ b/drivers/gpu/drm/drm_self_refresh_helper.c > > > @@ -5,6 +5,7 @@ > > > * Authors: > > > * Sean Paul <seanpaul@chromium.org> > > > */ > > > +#include <linux/average.h> > > > #include <linux/bitops.h> > > > #include <linux/slab.h> > > > #include <linux/workqueue.h> > > > @@ -50,10 +51,17 @@ > > > * atomic_check when &drm_crtc_state.self_refresh_active is true. > > > */ > > > > > > +#define SELF_REFRESH_AVG_SEED_MS 200 > > > + > > > +DECLARE_EWMA(psr_time, 4, 4) > > > + > > > struct drm_self_refresh_data { > > > struct drm_crtc *crtc; > > > struct delayed_work entry_work; > > > - unsigned int entry_delay_ms; > > > + > > > + struct mutex avg_mutex; > > > + struct ewma_psr_time entry_avg_ms; > > > + struct ewma_psr_time exit_avg_ms; > > > }; > > > > > > static void drm_self_refresh_helper_entry_work(struct work_struct *work) > > > @@ -121,6 +129,44 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) > > > drm_modeset_acquire_fini(&ctx); > > > } > > > > > > +/** > > > + * 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 > > > + * > > > + * 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) > > > +{ > > > + struct drm_crtc *crtc; > > > + struct drm_crtc_state *old_crtc_state, *new_crtc_state; > > > + int i; > > > + > > > + for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, > > > + new_crtc_state, i) { > > > + struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > > > + struct ewma_psr_time *time; > > > + > > > + if (old_crtc_state->self_refresh_active == > > > + new_crtc_state->self_refresh_active) > > > + continue; > > > + > > > + if (new_crtc_state->self_refresh_active) > > > + time = &sr_data->entry_avg_ms; > > > + else > > > + time = &sr_data->exit_avg_ms; > > > + > > > + mutex_lock(&sr_data->avg_mutex); > > > + ewma_psr_time_add(time, commit_time_ms); > > > + mutex_unlock(&sr_data->avg_mutex); > > > + } > > > +} > > > +EXPORT_SYMBOL(drm_self_refresh_helper_update_avg_times); > > > + > > > /** > > > * drm_self_refresh_helper_alter_state - Alters the atomic state for SR exit > > > * @state: the state currently being checked > > > @@ -152,6 +198,7 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > > > > > > for_each_new_crtc_in_state(state, crtc, crtc_state, i) { > > > struct drm_self_refresh_data *sr_data; > > > + unsigned int delay; > > > > > > /* Don't trigger the entry timer when we're already in SR */ > > > if (crtc_state->self_refresh_active) > > > @@ -161,8 +208,13 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > > > if (!sr_data) > > > continue; > > > > > > + mutex_lock(&sr_data->avg_mutex); > > > + delay = (ewma_psr_time_read(&sr_data->entry_avg_ms) + > > > + ewma_psr_time_read(&sr_data->exit_avg_ms)) * 2; > > > + mutex_unlock(&sr_data->avg_mutex); > > > + > > > mod_delayed_work(system_wq, &sr_data->entry_work, > > > - msecs_to_jiffies(sr_data->entry_delay_ms)); > > > + msecs_to_jiffies(delay)); > > > } > > > } > > > EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > > > @@ -170,12 +222,10 @@ EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > > > /** > > > * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc > > > * @crtc: the crtc which supports self refresh supported displays > > > - * @entry_delay_ms: amount of inactivity to wait before entering self refresh > > > * > > > * Returns zero if successful or -errno on failure > > > */ > > > -int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > > - unsigned int entry_delay_ms) > > > +int drm_self_refresh_helper_init(struct drm_crtc *crtc) > > > { > > > struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > > > > > > @@ -189,8 +239,18 @@ int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > > > > > INIT_DELAYED_WORK(&sr_data->entry_work, > > > drm_self_refresh_helper_entry_work); > > > - sr_data->entry_delay_ms = entry_delay_ms; > > > sr_data->crtc = crtc; > > > + mutex_init(&sr_data->avg_mutex); > > > + ewma_psr_time_init(&sr_data->entry_avg_ms); > > > + ewma_psr_time_init(&sr_data->exit_avg_ms); > > > + > > > + /* > > > + * Seed the averages so they're non-zero (and sufficiently large > > > + * for even poorly performing panels). As time goes on, this will be > > > + * averaged out and the values will trend to their true value. > > > + */ > > > + ewma_psr_time_add(&sr_data->entry_avg_ms, SELF_REFRESH_AVG_SEED_MS); > > > + ewma_psr_time_add(&sr_data->exit_avg_ms, SELF_REFRESH_AVG_SEED_MS); > > > > > > crtc->self_refresh_data = sr_data; > > > return 0; > > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > > > index 2f821c58007c..613404f86668 100644 > > > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > > > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c > > > @@ -39,8 +39,6 @@ > > > #include "rockchip_drm_vop.h" > > > #include "rockchip_rgb.h" > > > > > > -#define VOP_SELF_REFRESH_ENTRY_DELAY_MS 100 > > > - > > > #define VOP_WIN_SET(vop, win, name, v) \ > > > vop_reg_set(vop, &win->phy->name, win->base, ~0, v, #name) > > > #define VOP_SCL_SET(vop, win, name, v) \ > > > @@ -1563,8 +1561,7 @@ static int vop_create_crtc(struct vop *vop) > > > init_completion(&vop->line_flag_completion); > > > crtc->port = port; > > > > > > - ret = drm_self_refresh_helper_init(crtc, > > > - VOP_SELF_REFRESH_ENTRY_DELAY_MS); > > > + ret = drm_self_refresh_helper_init(crtc); > > > if (ret) > > > DRM_DEV_DEBUG_KMS(vop->dev, > > > "Failed to init %s with SR helpers %d, ignoring\n", > > > diff --git a/include/drm/drm_self_refresh_helper.h b/include/drm/drm_self_refresh_helper.h > > > index 397a583ccca7..5b79d253fb46 100644 > > > --- a/include/drm/drm_self_refresh_helper.h > > > +++ b/include/drm/drm_self_refresh_helper.h > > > @@ -12,9 +12,9 @@ struct drm_atomic_state; > > > struct drm_crtc; > > > > > > void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state); > > > +void drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state, > > > + unsigned int commit_time_ms); > > > > > > -int drm_self_refresh_helper_init(struct drm_crtc *crtc, > > > - unsigned int entry_delay_ms); > > > - > > > +int drm_self_refresh_helper_init(struct drm_crtc *crtc); > > > void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc); > > > #endif > > > -- > > > Sean Paul, Software Engineer, Google / Chromium OS > > > > > > > -- > > Sean Paul, Software Engineer, Google / Chromium OS > > _______________________________________________ > > dri-devel mailing list > > dri-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-11-04 17:27 UTC | newest]
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[not found] <20190918200734.149876-1-sean@poorly.run>
2019-09-18 20:07 ` [PATCH v2 2/3] drm: Measure Self Refresh Entry/Exit times to avoid thrashing Sean Paul
2019-09-19 14:14 ` Sean Paul
2019-10-30 16:59 ` Enric Balletbo Serra
2019-11-04 17:26 ` Enric Balletbo Serra
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