From patchwork Sat Oct 2 16:36:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 12532255 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 462A1C433FE for ; Sat, 2 Oct 2021 16:36:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D20D61A50 for ; Sat, 2 Oct 2021 16:36:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233650AbhJBQie (ORCPT ); Sat, 2 Oct 2021 12:38:34 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44288 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233648AbhJBQic (ORCPT ); Sat, 2 Oct 2021 12:38:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633192605; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ua054J7EUVY9C7XxKhZDym/c+dWM7BBc56xLXjW2Q3Y=; b=ArclE17J5SpNlqgCTGeS3f+t9xJ+IntNW4jOarVZwvA7QUUtr2ikPDKqMhZYhL18qOij6Q udgCGKl6fKxnpYPL6HEx/wDx4Ddo+LxlzbBaG0F5Nst9ALiSgX6ChgMbJrs8V1KvKKw1Es yuugMJkC2jmWExDRFMoTH9kDi98+nA0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-295-vEFyxMxRP5u2ldD8e6by6w-1; Sat, 02 Oct 2021 12:36:44 -0400 X-MC-Unique: vEFyxMxRP5u2ldD8e6by6w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C1CEB1023F4D; Sat, 2 Oct 2021 16:36:41 +0000 (UTC) Received: from x1.localdomain (unknown [10.39.192.31]) by smtp.corp.redhat.com (Postfix) with ESMTP id D4E6A100763D; Sat, 2 Oct 2021 16:36:37 +0000 (UTC) From: Hans de Goede To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rajat Jain , Jani Nikula , Lyude , Joonas Lahtinen , Rodrigo Vivi , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , Mark Gross , Andy Shevchenko Cc: Hans de Goede , Daniel Vetter , David Airlie , Pekka Paalanen , Mario Limonciello , Mark Pearson , Sebastien Bacher , Marco Trevisan , Emil Velikov , intel-gfx , dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org Subject: [PATCH 04/10] drm/privacy-screen: Add notifier support (v2) Date: Sat, 2 Oct 2021 18:36:12 +0200 Message-Id: <20211002163618.99175-5-hdegoede@redhat.com> In-Reply-To: <20211002163618.99175-1-hdegoede@redhat.com> References: <20211002163618.99175-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Add support for privacy-screen consumers to register a notifier to be notified of external (e.g. done by the hw itself on a hotkey press) state changes. Changes in v2: - Drop WARN_ON(mutex_is_locked(&priv->lock)) check in drm_privacy_screen_call_notifier_chain() it may be locked by another thread, which would lead to a false-positive triggering of the check Reviewed-by: Emil Velikov Reviewed-by: Lyude Paul Signed-off-by: Hans de Goede --- drivers/gpu/drm/drm_privacy_screen.c | 64 +++++++++++++++++++++++ include/drm/drm_privacy_screen_consumer.h | 15 ++++++ include/drm/drm_privacy_screen_driver.h | 4 ++ 3 files changed, 83 insertions(+) diff --git a/drivers/gpu/drm/drm_privacy_screen.c b/drivers/gpu/drm/drm_privacy_screen.c index 183a6011adf0..beaf99e9120a 100644 --- a/drivers/gpu/drm/drm_privacy_screen.c +++ b/drivers/gpu/drm/drm_privacy_screen.c @@ -257,6 +257,49 @@ void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, } EXPORT_SYMBOL(drm_privacy_screen_get_state); +/** + * drm_privacy_screen_register_notifier - register a notifier + * @priv: Privacy screen to register the notifier with + * @nb: Notifier-block for the notifier to register + * + * Register a notifier with the privacy-screen to be notified of changes made + * to the privacy-screen state from outside of the privacy-screen class. + * E.g. the state may be changed by the hardware itself in response to a + * hotkey press. + * + * The notifier is called with no locks held. The new hw_state and sw_state + * can be retrieved using the drm_privacy_screen_get_state() function. + * A pointer to the drm_privacy_screen's struct is passed as the void *data + * argument of the notifier_block's notifier_call. + * + * The notifier will NOT be called when changes are made through + * drm_privacy_screen_set_sw_state(). It is only called for external changes. + * + * Return: 0 on success, negative error code on failure. + */ +int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, + struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&priv->notifier_head, nb); +} +EXPORT_SYMBOL(drm_privacy_screen_register_notifier); + +/** + * drm_privacy_screen_unregister_notifier - unregister a notifier + * @priv: Privacy screen to register the notifier with + * @nb: Notifier-block for the notifier to register + * + * Unregister a notifier registered with drm_privacy_screen_register_notifier(). + * + * Return: 0 on success, negative error code on failure. + */ +int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, + struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&priv->notifier_head, nb); +} +EXPORT_SYMBOL(drm_privacy_screen_unregister_notifier); + /*** drm_privacy_screen_driver.h functions ***/ static ssize_t sw_state_show(struct device *dev, @@ -354,6 +397,7 @@ struct drm_privacy_screen *drm_privacy_screen_register( return ERR_PTR(-ENOMEM); mutex_init(&priv->lock); + BLOCKING_INIT_NOTIFIER_HEAD(&priv->notifier_head); priv->dev.class = drm_class; priv->dev.type = &drm_privacy_screen_type; @@ -401,3 +445,23 @@ void drm_privacy_screen_unregister(struct drm_privacy_screen *priv) device_unregister(&priv->dev); } EXPORT_SYMBOL(drm_privacy_screen_unregister); + +/** + * drm_privacy_screen_call_notifier_chain - notify consumers of state change + * @priv: Privacy screen to register the notifier with + * + * A privacy-screen provider driver can call this functions upon external + * changes to the privacy-screen state. E.g. the state may be changed by the + * hardware itself in response to a hotkey press. + * This function must be called without holding the privacy-screen lock. + * the driver must update sw_state and hw_state to reflect the new state before + * calling this function. + * The expected behavior from the driver upon receiving an external state + * change event is: 1. Take the lock; 2. Update sw_state and hw_state; + * 3. Release the lock. 4. Call drm_privacy_screen_call_notifier_chain(). + */ +void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv) +{ + blocking_notifier_call_chain(&priv->notifier_head, 0, priv); +} +EXPORT_SYMBOL(drm_privacy_screen_call_notifier_chain); diff --git a/include/drm/drm_privacy_screen_consumer.h b/include/drm/drm_privacy_screen_consumer.h index 0cbd23b0453d..7f66a90d15b7 100644 --- a/include/drm/drm_privacy_screen_consumer.h +++ b/include/drm/drm_privacy_screen_consumer.h @@ -24,6 +24,11 @@ int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv, void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, enum drm_privacy_screen_status *sw_state_ret, enum drm_privacy_screen_status *hw_state_ret); + +int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, + struct notifier_block *nb); +int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, + struct notifier_block *nb); #else static inline struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev, const char *con_id) @@ -45,6 +50,16 @@ static inline void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, *sw_state_ret = PRIVACY_SCREEN_DISABLED; *hw_state_ret = PRIVACY_SCREEN_DISABLED; } +static inline int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, + struct notifier_block *nb) +{ + return -ENODEV; +} +static inline int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, + struct notifier_block *nb) +{ + return -ENODEV; +} #endif #endif diff --git a/include/drm/drm_privacy_screen_driver.h b/include/drm/drm_privacy_screen_driver.h index 5187ae52eb03..24591b607675 100644 --- a/include/drm/drm_privacy_screen_driver.h +++ b/include/drm/drm_privacy_screen_driver.h @@ -54,6 +54,8 @@ struct drm_privacy_screen { struct mutex lock; /** @list: privacy-screen devices list list-entry. */ struct list_head list; + /** @notifier_head: privacy-screen notifier head. */ + struct blocking_notifier_head notifier_head; /** * @ops: &struct drm_privacy_screen_ops for this privacy-screen. * This is NULL if the driver has unregistered the privacy-screen. @@ -77,4 +79,6 @@ struct drm_privacy_screen *drm_privacy_screen_register( struct device *parent, const struct drm_privacy_screen_ops *ops); void drm_privacy_screen_unregister(struct drm_privacy_screen *priv); +void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv); + #endif