On Thu, Nov 4, 2021 at 12:40 AM Brian Norris <briannorris@xxxxxxxxxxxx> wrote: > > To improve panel self-refresh exit latency, we speculatively start > exiting when we > receive input events. Occasionally, this may lead to false positives, > but most of the time we get a head start on coming out of PSR. Depending > on how userspace takes to produce a new frame in response to the event, > this can completely hide the exit latency. > > In local tests on Chrome OS (Rockchip RK3399 eDP), we've found that the > input notifier gives us about a 50ms head start over the > fb-update-initiated exit. > > Leverage a new drm_input_helper library to get easy access to > likely-relevant input event callbacks. > > Inspired-by: Kristian H. Kristensen <hoegsberg@xxxxxxxxxx> > Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx> Can you pls resend with dri-devel on cc? scripts/get_maintainers.pl should pick this up, you have all the maintainers but not the list. -Daniel > --- > This was in part picked up from: > > https://lore.kernel.org/all/20180405095000.9756-25-enric.balletbo@xxxxxxxxxxxxx/ > [PATCH v6 24/30] drm/rockchip: Disable PSR on input events > > with significant rewrites/reworks: > > - moved to common drm_input_helper and drm_self_refresh_helper > implementation > - track state only through crtc->state->self_refresh_active > > Note that I'm relatively unfamiliar with DRM locking expectations, but I > believe access to drm_crtc->state (which helps us track redundant > transitions) is OK under the locking provided by > drm_atomic_get_crtc_state(). > > drivers/gpu/drm/drm_self_refresh_helper.c | 54 ++++++++++++++++++++--- > 1 file changed, 48 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c > index dd33fec5aabd..dcab061cc90a 100644 > --- a/drivers/gpu/drm/drm_self_refresh_helper.c > +++ b/drivers/gpu/drm/drm_self_refresh_helper.c > @@ -15,6 +15,7 @@ > #include <drm/drm_connector.h> > #include <drm/drm_crtc.h> > #include <drm/drm_device.h> > +#include <drm/drm_input_helper.h> > #include <drm/drm_mode_config.h> > #include <drm/drm_modeset_lock.h> > #include <drm/drm_print.h> > @@ -58,17 +59,17 @@ DECLARE_EWMA(psr_time, 4, 4) > struct drm_self_refresh_data { > struct drm_crtc *crtc; > struct delayed_work entry_work; > + struct work_struct exit_work; > + struct drm_input_handler input_handler; > > 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) > +static void drm_self_refresh_transition(struct drm_self_refresh_data *sr_data, > + bool enable) > { > - struct drm_self_refresh_data *sr_data = container_of( > - to_delayed_work(work), > - struct drm_self_refresh_data, entry_work); > struct drm_crtc *crtc = sr_data->crtc; > struct drm_device *dev = crtc->dev; > struct drm_modeset_acquire_ctx ctx; > @@ -95,6 +96,9 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) > goto out; > } > > + if (crtc->state->self_refresh_active == enable) > + goto out; > + > if (!crtc_state->enable) > goto out; > > @@ -107,8 +111,8 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) > goto out; > } > > - crtc_state->active = false; > - crtc_state->self_refresh_active = true; > + crtc_state->active = !enable; > + crtc_state->self_refresh_active = enable; > > ret = drm_atomic_commit(state); > if (ret) > @@ -129,6 +133,15 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) > drm_modeset_acquire_fini(&ctx); > } > > +static void drm_self_refresh_helper_entry_work(struct work_struct *work) > +{ > + struct drm_self_refresh_data *sr_data = container_of( > + to_delayed_work(work), > + struct drm_self_refresh_data, entry_work); > + > + drm_self_refresh_transition(sr_data, true); > +} > + > /** > * drm_self_refresh_helper_update_avg_times - Updates a crtc's SR time averages > * @state: the state which has just been applied to hardware > @@ -223,6 +236,20 @@ void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state) > } > EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > > +static void drm_self_refresh_helper_exit_work(struct work_struct *work) > +{ > + struct drm_self_refresh_data *sr_data = container_of( > + work, struct drm_self_refresh_data, exit_work); > + > + drm_self_refresh_transition(sr_data, false); > +} > + > +static void drm_self_refresh_input_event(void *data) > +{ > + struct drm_self_refresh_data *sr_data = data; > + > + schedule_work(&sr_data->exit_work); > +} > /** > * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc > * @crtc: the crtc which supports self refresh supported displays > @@ -232,6 +259,7 @@ EXPORT_SYMBOL(drm_self_refresh_helper_alter_state); > int drm_self_refresh_helper_init(struct drm_crtc *crtc) > { > struct drm_self_refresh_data *sr_data = crtc->self_refresh_data; > + int ret; > > /* Helper is already initialized */ > if (WARN_ON(sr_data)) > @@ -243,6 +271,7 @@ int drm_self_refresh_helper_init(struct drm_crtc *crtc) > > INIT_DELAYED_WORK(&sr_data->entry_work, > drm_self_refresh_helper_entry_work); > + INIT_WORK(&sr_data->exit_work, drm_self_refresh_helper_exit_work); > sr_data->crtc = crtc; > mutex_init(&sr_data->avg_mutex); > ewma_psr_time_init(&sr_data->entry_avg_ms); > @@ -256,8 +285,19 @@ int drm_self_refresh_helper_init(struct drm_crtc *crtc) > 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); > > + sr_data->input_handler.callback = drm_self_refresh_input_event; > + sr_data->input_handler.priv = sr_data; > + ret = drm_input_handle_register(crtc->dev, &sr_data->input_handler); > + if (ret) > + goto err; > + > crtc->self_refresh_data = sr_data; > + > return 0; > + > +err: > + kfree(sr_data); > + return ret; > } > EXPORT_SYMBOL(drm_self_refresh_helper_init); > > @@ -275,7 +315,9 @@ void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc) > > crtc->self_refresh_data = NULL; > > + drm_input_handle_unregister(&sr_data->input_handler); > cancel_delayed_work_sync(&sr_data->entry_work); > + cancel_work_sync(&sr_data->exit_work); > kfree(sr_data); > } > EXPORT_SYMBOL(drm_self_refresh_helper_cleanup); > -- > 2.34.0.rc0.344.g81b53c2807-goog > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
