From patchwork Wed Nov 17 22:48:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brian Norris X-Patchwork-Id: 12625719 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B309C433F5 for ; Wed, 17 Nov 2021 22:49:13 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 177DE6124B for ; Wed, 17 Nov 2021 22:49:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 177DE6124B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ED2B96E145; Wed, 17 Nov 2021 22:49:10 +0000 (UTC) Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by gabe.freedesktop.org (Postfix) with ESMTPS id 79B356E145 for ; Wed, 17 Nov 2021 22:49:09 +0000 (UTC) Received: by mail-pg1-x52c.google.com with SMTP id q12so3548115pgh.5 for ; Wed, 17 Nov 2021 14:49:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=PRAN3rr2nPVo3gIjlESQaB8ebBDc+D/e6ANLJIK5y4s=; b=BcR+4Lz3vAnsR3uoPEuqtYS/bHo6Vvi8O1qPuLresu/Y5qW84EQaQdowja+Qzu250b EL34dpX72GmpldCBF3QbRbZO4y2+Yjdxv/nvbFhKVNffI+7PUmwqBHafNjTlbfq3EbfP 2ymP/ibAW7xVQ6UT2l2HanNP+pWtwU6rygk5I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=PRAN3rr2nPVo3gIjlESQaB8ebBDc+D/e6ANLJIK5y4s=; b=2bNmVyRLeyz2Sjx1v04zjSeR2ug5gR51dnV7mrXWuhivUg15tt7j5g1UrlIC+J4k7t T+Iy8twS1h4YJyC0Y8AeQdFM0WVUjY3OBOBqudkllbu0n0BuVsqZ8DgrlsZlSBDiPROi 3SJrrOoQlNV1BmWH5qVSaGM/zVCblLvvJYWA5A+tHf1NkvqIiLrI3zzwClYKyrIzpyG7 1FPV6YrnLn6cVlobtwqnFMummNaM5pTVFexXW5v73vblGDzaKU9swP7wz+6KBNT13/XN SkKfNW6oCJNbZsLVEli0+Bcr03HDwUhWRXUemmrL0zCU8oyOUH0SsLTH5CY+rtaWXsGX eC6w== X-Gm-Message-State: AOAM5328XV199m83z9S0riFtYKmpvnYzLUGpCslmbqzsixrQr9XQ295S wmAHiIbJd2lbl/vS4A8EP2kIXA== X-Google-Smtp-Source: ABdhPJxaitq98GLKg68E2jnoQ7v3i9kV5Qhy51dVJ9vt8oTBXNj7KdRjTAyA98irH+itT7XU42Xz5Q== X-Received: by 2002:a05:6a00:10c5:b0:49f:de2c:1b23 with SMTP id d5-20020a056a0010c500b0049fde2c1b23mr10358091pfu.41.1637189348986; Wed, 17 Nov 2021 14:49:08 -0800 (PST) Received: from localhost ([2620:15c:202:201:896b:df38:4eae:c568]) by smtp.gmail.com with UTF8SMTPSA id h8sm702003pfh.10.2021.11.17.14.49.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Nov 2021 14:49:08 -0800 (PST) From: Brian Norris To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann Subject: [PATCH v2 2/2] drm/self_refresh: Disable self-refresh on input events Date: Wed, 17 Nov 2021 14:48:41 -0800 Message-Id: <20211117144807.v2.2.Ie6c485320b35b89fd49e15a73f0a68e3bb49eef9@changeid> X-Mailer: git-send-email 2.34.0.rc1.387.gb447b232ab-goog In-Reply-To: <20211117224841.3442482-1-briannorris@chromium.org> References: <20211117224841.3442482-1-briannorris@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rob Clark , Brian Norris , David Airlie , Dmitry Torokhov , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Doug Anderson , linux-rockchip@lists.infradead.org, "Kristian H . Kristensen" , Andrzej Hajda , linux-input@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 Signed-off-by: Brian Norris --- This was in part picked up from: https://lore.kernel.org/all/20180405095000.9756-25-enric.balletbo@collabora.com/ [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(). Changes in v2: - Delay PSR re-entry, when already disabled - Allow default configuration via Kconfig and modparam - Replace void* with container_of() drivers/gpu/drm/Kconfig | 16 ++++ drivers/gpu/drm/drm_self_refresh_helper.c | 98 +++++++++++++++++++---- 2 files changed, 100 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 381476b10a9d..698924ed9b6b 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -84,6 +84,22 @@ config DRM_INPUT_HELPER depends on DRM_KMS_HELPER depends on INPUT +config DRM_SELF_REFRESH_INPUT_BOOST_DEFAULT + bool "Preemptively exit panel self-refresh on input device activity" if EXPERT + default y + depends on DRM_INPUT_HELPER + help + Allows the generic DRM panel self-refresh helpers to factor in user + input activity to preemptively exit panel self-refresh, in order to + reduce potentially-visible latency when displaying new display + content. This is an optimization which often will do the right thing, + but can be disabled for experimentation or similar. + + Saying Y enables the feature by default; this can also be configured + by module parameter, drm_kms_helper.self_refresh_input_boost. + + If in doubt, say "Y". + config DRM_KMS_HELPER tristate depends on DRM diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c index dd33fec5aabd..ba4881e683b7 100644 --- a/drivers/gpu/drm/drm_self_refresh_helper.c +++ b/drivers/gpu/drm/drm_self_refresh_helper.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -15,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -58,17 +60,41 @@ 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; + bool input_handler_registered; 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 bool self_refresh_input_boost = + IS_ENABLED(CONFIG_DRM_SELF_REFRESH_INPUT_BOOST_DEFAULT); +#if defined(CONFIG_DRM_INPUT_HELPER) +module_param(self_refresh_input_boost, bool, 0644); +MODULE_PARM_DESC(self_refresh_input_boost, + "Enable panel self-refresh input boost [default=" + __stringify(CONFIG_DRM_SELF_REFRESH_INPUT_BOOST_DEFAULT) "]"); +#endif /* CONFIG_DRM_INPUT_HELPER */ + + +static void drm_self_refresh_reschedule(struct drm_self_refresh_data *sr_data) +{ + unsigned int delay; + + 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(delay)); +} + +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 +121,14 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work) goto out; } + if (crtc->state->self_refresh_active == enable) { + /* Exiting SR; delay re-entry for at least one more cycle. */ + if (!enable) + drm_self_refresh_reschedule(sr_data); + + goto out; + } + if (!crtc_state->enable) goto out; @@ -107,8 +141,8 @@ 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 +163,15 @@ 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 @@ -202,7 +245,6 @@ 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) @@ -212,17 +254,26 @@ 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(delay)); + drm_self_refresh_reschedule(sr_data); } } 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(struct drm_input_handler *handler) +{ + struct drm_self_refresh_data *sr_data = container_of( + handler, struct drm_self_refresh_data, input_handler); + + 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 +283,7 @@ 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 +295,7 @@ 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 +309,22 @@ 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); + if (self_refresh_input_boost) { + sr_data->input_handler.callback = drm_self_refresh_input_event; + ret = drm_input_handle_register(crtc->dev, + &sr_data->input_handler); + if (ret) + goto err; + sr_data->input_handler_registered = true; + } + crtc->self_refresh_data = sr_data; + return 0; + +err: + kfree(sr_data); + return ret; } EXPORT_SYMBOL(drm_self_refresh_helper_init); @@ -275,7 +342,10 @@ void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc) crtc->self_refresh_data = NULL; + if (sr_data->input_handler_registered) + 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);