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 654C4C433F5 for ; Thu, 18 Nov 2021 09:06:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C6E860462 for ; Thu, 18 Nov 2021 09:06:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243007AbhKRJJQ (ORCPT ); Thu, 18 Nov 2021 04:09:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245028AbhKRJIP (ORCPT ); Thu, 18 Nov 2021 04:08:15 -0500 Received: from mail-ed1-x534.google.com (mail-ed1-x534.google.com [IPv6:2a00:1450:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D1F5C0613B9 for ; Thu, 18 Nov 2021 01:05:15 -0800 (PST) Received: by mail-ed1-x534.google.com with SMTP id l25so7400561eda.11 for ; Thu, 18 Nov 2021 01:05:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=lXnv3StCz6QOJgzKo0TU0WtB9sNFJ2NEu70wfyrmomU=; b=HSCFnNZdlXyl+vXxXJE2gHtqTi/WFPXBQfVGJRTbDNCC8d3FL37LjuRLAH3PllB6C7 qAGaSKiJ6Dw6zvW8LfkEfmdVBSbxmIA39VqrLicnQ0PzgoUV8+BI+kw5BKGYaaRKm+PN ty4/h2ion6eBIk7tnQ3/Up6okNbJYrOHT6L5E= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=lXnv3StCz6QOJgzKo0TU0WtB9sNFJ2NEu70wfyrmomU=; b=N++08TKdayjAVHpjS41Kpuo2gxkxm8nD2qYc/lWrFB7w/i/dcEj6ru7qKmHHuNYTgL DApW7kUuW6CwU8ouS7fbbTDXnqFFrgO8V2RHlPIbinMwVLjf5dzlUDHxzFls9ZxkbRvK j/S+mte/RY56Cl3nEAvHn2sshsIgpbqZdfjNeXZgTQ19FvIO9ATQf6FXtjiAjaD5/mgz n5atrcrv+Ni2LFJtiM02EtlankuyWUbrFAQLvSpiarbBxmkit3wCqgZIxQ3V2icY/AKG hyPe+OuRe5VZAf5EBYVaWEjm5WxD4VL4NnupJ88pm/tMXn8xqahcCiXYS4tF7DzG4Q+f 18uA== X-Gm-Message-State: AOAM531BtycfmwcuSHKSXXW/Nn5wO0apvkvakptK/UEk4lLPrqYVWLnf 9oLTkZTQr4agTNrtcxwVUlhCPA== X-Google-Smtp-Source: ABdhPJylQ8JBdXxl0Xb2D3tJ7cosBlu1Mj8PTO+yC7edF/HmQtFMt97ubDhZlPf8+OCdHzz0n+uziA== X-Received: by 2002:a05:6402:2751:: with SMTP id z17mr8692761edd.296.1637226314076; Thu, 18 Nov 2021 01:05:14 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id v10sm1229647edt.24.2021.11.18.01.05.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Nov 2021 01:05:13 -0800 (PST) Date: Thu, 18 Nov 2021 10:05:11 +0100 From: Daniel Vetter To: Brian Norris Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , "Kristian H . Kristensen" , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, Dmitry Torokhov , Doug Anderson , Andrzej Hajda , Rob Clark , linux-input@vger.kernel.org, Rob Clark , Daniel Vetter , David Airlie , dri-devel@lists.freedesktop.org Subject: Re: [PATCH v2 1/2] drm/input_helper: Add new input-handling helper Message-ID: Mail-Followup-To: Brian Norris , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , "Kristian H . Kristensen" , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, Dmitry Torokhov , Doug Anderson , Andrzej Hajda , Rob Clark , linux-input@vger.kernel.org, Rob Clark , David Airlie , dri-devel@lists.freedesktop.org References: <20211117224841.3442482-1-briannorris@chromium.org> <20211117144807.v2.1.I09b516eff75ead160a6582dd557e7e7e900c9e8e@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211117144807.v2.1.I09b516eff75ead160a6582dd557e7e7e900c9e8e@changeid> X-Operating-System: Linux phenom 5.10.0-8-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 17, 2021 at 02:48:40PM -0800, Brian Norris wrote: > A variety of applications have found it useful to listen to > user-initiated input events to make decisions within a DRM driver, given > that input events are often the first sign that we're going to start > doing latency-sensitive activities: > > * Panel self-refresh: software-directed self-refresh (e.g., with > Rockchip eDP) is especially latency sensitive. In some cases, it can > take 10s of milliseconds for a panel to exit self-refresh, which can > be noticeable. Rockchip RK3399 Chrome OS systems have always shipped > with an input_handler boost, that preemptively exits self-refresh > whenever there is input activity. > > * GPU drivers: on GPU-accelerated desktop systems, we may need to > render new frames immediately after user activity. Powering up the > GPU can take enough time that it is worthwhile to start this process > as soon as there is input activity. Many Chrome OS systems also ship > with an input_handler boost that powers up the GPU. > > This patch provides a small helper library that abstracts some of the > input-subsystem details around picking which devices to listen to, and > some other boilerplate. This will be used in the next patch to implement > the first bullet: preemptive exit for panel self-refresh. > > Bits of this are adapted from code the Android and/or Chrome OS kernels > have been carrying for a while. > > Signed-off-by: Brian Norris > --- > > Changes in v2: > - Honor CONFIG_INPUT dependency, via new CONFIG_DRM_INPUT_HELPER > - Remove void*; users should use container_of() > - Document the callback context > > drivers/gpu/drm/Kconfig | 6 ++ > drivers/gpu/drm/Makefile | 2 + > drivers/gpu/drm/drm_input_helper.c | 143 +++++++++++++++++++++++++++++ > include/drm/drm_input_helper.h | 41 +++++++++ Please add documentation for this and include it under Documentation/gpu/drm-kms-helpers.rst in a suitable place. Standards for core code should be overview DOC: with references to key functions/structs, and all driver visible structs, functions (static inline in header or exported) fully documented. > 4 files changed, 192 insertions(+) > create mode 100644 drivers/gpu/drm/drm_input_helper.c > create mode 100644 include/drm/drm_input_helper.h > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index fb144617055b..381476b10a9d 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -79,9 +79,15 @@ config DRM_DEBUG_SELFTEST > > If in doubt, say "N". > > +config DRM_INPUT_HELPER > + def_bool y > + depends on DRM_KMS_HELPER > + depends on INPUT Uh please no configs for each thing, it just makes everything more complex. Do we _really_ need this? > + > config DRM_KMS_HELPER > tristate > depends on DRM > + select DRM_INPUT_HELPER if INPUT > help > CRTC helpers for KMS drivers. > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > index 1c41156deb5f..9a6494aa45e6 100644 > --- a/drivers/gpu/drm/Makefile > +++ b/drivers/gpu/drm/Makefile > @@ -56,6 +56,8 @@ drm_kms_helper-y := drm_bridge_connector.o drm_crtc_helper.o drm_dp_helper.o \ > drm_atomic_state_helper.o drm_damage_helper.o \ > drm_format_helper.o drm_self_refresh_helper.o drm_rect.o > > +drm_kms_helper-$(CONFIG_DRM_INPUT_HELPER) += drm_input_helper.o > + > drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o > drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o > drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o > diff --git a/drivers/gpu/drm/drm_input_helper.c b/drivers/gpu/drm/drm_input_helper.c > new file mode 100644 > index 000000000000..470f90865c7c > --- /dev/null > +++ b/drivers/gpu/drm/drm_input_helper.c > @@ -0,0 +1,143 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2021 Google, Inc. > + */ > +#include > +#include > + > +#include > +#include > + > +/** > + * DOC: overview > + * > + * This helper library provides a thin wrapper around input handles, so that > + * DRM drivers can easily perform domain-specific actions in response to user > + * activity. e.g., if someone is moving a mouse, we're likely to want to > + * display something soon, and we should exit panel self-refresh. > + */ > + > +static void drm_input_event(struct input_handle *handle, unsigned int type, > + unsigned int code, int value) > +{ > + struct drm_input_handler *handler = handle->handler->private; > + > + handler->callback(handler); > +} > + > +static int drm_input_connect(struct input_handler *handler, > + struct input_dev *dev, > + const struct input_device_id *id) > +{ > + struct input_handle *handle; > + int error; > + > + handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); > + if (!handle) > + return -ENOMEM; > + > + handle->dev = dev; > + handle->handler = handler; > + handle->name = "drm-input-helper"; > + > + error = input_register_handle(handle); > + if (error) > + goto err2; > + > + error = input_open_device(handle); > + if (error) > + goto err1; > + > + return 0; > + > +err1: > + input_unregister_handle(handle); > +err2: > + kfree(handle); > + return error; > +} > + > +static void drm_input_disconnect(struct input_handle *handle) > +{ > + input_close_device(handle); > + input_unregister_handle(handle); > + kfree(handle); > +} > + > +static const struct input_device_id drm_input_ids[] = { > + { > + .flags = INPUT_DEVICE_ID_MATCH_EVBIT | > + INPUT_DEVICE_ID_MATCH_ABSBIT, > + .evbit = { BIT_MASK(EV_ABS) }, > + .absbit = { [BIT_WORD(ABS_MT_POSITION_X)] = > + BIT_MASK(ABS_MT_POSITION_X) | > + BIT_MASK(ABS_MT_POSITION_Y) }, > + }, /* multi-touch touchscreen */ > + { > + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, > + .evbit = { BIT_MASK(EV_ABS) }, > + .absbit = { [BIT_WORD(ABS_X)] = BIT_MASK(ABS_X) } > + > + }, /* stylus or joystick device */ > + { > + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, > + .evbit = { BIT_MASK(EV_KEY) }, > + .keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) }, > + }, /* pointer (e.g. trackpad, mouse) */ > + { > + .flags = INPUT_DEVICE_ID_MATCH_EVBIT, > + .evbit = { BIT_MASK(EV_KEY) }, > + .keybit = { [BIT_WORD(KEY_ESC)] = BIT_MASK(KEY_ESC) }, > + }, /* keyboard */ > + { > + .flags = INPUT_DEVICE_ID_MATCH_EVBIT | > + INPUT_DEVICE_ID_MATCH_KEYBIT, > + .evbit = { BIT_MASK(EV_KEY) }, > + .keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) }, > + }, /* joysticks not caught by ABS_X above */ > + { > + .flags = INPUT_DEVICE_ID_MATCH_EVBIT | > + INPUT_DEVICE_ID_MATCH_KEYBIT, > + .evbit = { BIT_MASK(EV_KEY) }, > + .keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) }, > + }, /* gamepad */ > + { }, > +}; > + > +int drm_input_handle_register(struct drm_device *dev, > + struct drm_input_handler *handler) > +{ > + int ret; > + > + if (!handler->callback) > + return -EINVAL; > + > + handler->handler.event = drm_input_event; > + handler->handler.connect = drm_input_connect; > + handler->handler.disconnect = drm_input_disconnect; > + handler->handler.name = kasprintf(GFP_KERNEL, "drm-input-helper-%s", > + dev_name(dev->dev)); > + if (!handler->handler.name) > + return -ENOMEM; > + > + handler->handler.id_table = drm_input_ids; > + handler->handler.private = handler; > + > + ret = input_register_handler(&handler->handler); > + if (ret) > + goto err; > + > + return 0; > + > +err: > + kfree(handler->handler.name); > + return ret; > +} > +EXPORT_SYMBOL(drm_input_handle_register); > + > +void drm_input_handle_unregister(struct drm_input_handler *handler) > +{ > + input_unregister_handler(&handler->handler); > + kfree(handler->handler.name); > +} > +EXPORT_SYMBOL(drm_input_handle_unregister); > diff --git a/include/drm/drm_input_helper.h b/include/drm/drm_input_helper.h > new file mode 100644 > index 000000000000..7904f397b934 > --- /dev/null > +++ b/include/drm/drm_input_helper.h > @@ -0,0 +1,41 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (C) 2021 Google, Inc. > + */ > +#ifndef __DRM_INPUT_HELPER_H__ > +#define __DRM_INPUT_HELPER_H__ > + > +#include > + > +struct drm_device; > + > +struct drm_input_handler { > + /* > + * Callback to call for input activity. Will be called in an atomic > + * context. How atomic? Like hardirq, and nasty spinlocks held? > + */ > + void (*callback)(struct drm_input_handler *handler); > + > + struct input_handler handler; > +}; > + > +#if defined(CONFIG_DRM_INPUT_HELPER) > + > +int drm_input_handle_register(struct drm_device *dev, > + struct drm_input_handler *handler); > +void drm_input_handle_unregister(struct drm_input_handler *handler); > + > +#else /* !CONFIG_DRM_INPUT_HELPER */ > + > +static inline int drm_input_handle_register(struct drm_device *dev, > + struct drm_input_handler *handler) > +{ > + return 0; > +} I guess the reason behind the helper is that you also want to use this in drivers or maybe drm/sched? Anyway I think it looks all reasonable. Definitely need an ack from input people that the event list you have is a good choice, I have no idea what that all does. Maybe also document that part a bit more. -Daniel > + > +static inline void > +drm_input_handle_unregister(struct drm_input_handler *handler) {} > + > +#endif /* CONFIG_DRM_INPUT_HELPER */ > + > +#endif /* __DRM_INPUT_HELPER_H__ */ > -- > 2.34.0.rc1.387.gb447b232ab-goog > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch