From patchwork Tue Aug 27 16:42:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 21045 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id 469D9C323E for ; Tue, 27 Aug 2024 16:43:15 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id B1635634A6; Tue, 27 Aug 2024 18:43:14 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="CBZiyl76"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 7F6FC6345F for ; Tue, 27 Aug 2024 18:43:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724776989; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RXpgwKO8VIbb+Sgk69cR5a9qFLL+9PC3qGu/y1J0HLE=; b=CBZiyl76BZlsOniMIitvJFzn9hUQPovTEfi5qspWF2iPcBomZHxQymfg50zj/G4pGQ60wN hWp+wIJOcTZ2Tuf0DmAG//We3EjYHluchgdV74HRVS8lpHAaqXCJCeIoBQLGfuOPLfRHrW 5aKVStQ+UEnrpwwTDJ4N/pvJ+cGX8u8= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-519-ticvRDAjOLS_8nIc6gaVMw-1; Tue, 27 Aug 2024 12:43:08 -0400 X-MC-Unique: ticvRDAjOLS_8nIc6gaVMw-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2A0AE1955D53 for ; Tue, 27 Aug 2024 16:43:07 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.192.136]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CCCE51955D89; Tue, 27 Aug 2024 16:43:05 +0000 (UTC) From: Hans de Goede To: libcamera-devel@lists.libcamera.org Cc: Milan Zamazal , Maxime Ripard , Hans de Goede Subject: [PATCH v2 1/3] pipeline_handler: Add acquireDevice() method to mirror existing releaseDevice() Date: Tue, 27 Aug 2024 18:42:53 +0200 Message-ID: <20240827164255.314432-2-hdegoede@redhat.com> In-Reply-To: <20240827164255.314432-1-hdegoede@redhat.com> References: <20240827164255.314432-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" libcamera always keeps all /dev/video# and /dev/v4l2_subdev# nodes for a pipeline open after enumerating the camera. This is a problem for the uvcvideo pipeline handler. Keeping /dev/video# open stops the UVC USB device from being able to enter runtime-suspend causing significant unnecessary power-usage. Add a stub acquireDevice() method to the PipelineHandler class which pipeline handlers can override. The uvcvideo pipeline handler will use this to delay opening /dev/video# until the device is acquired. This is a special case because the kernel uvcvideo driver powers on the USB device as soon as /dev/video# is opened. This behavior should *not* be copied by other pipeline handlers. Signed-off-by: Hans de Goede Reviewed-by: Laurent Pinchart Reviewed-by: Harvey Yang --- Changes in v2: - Add a note to both the doxygen documentation as well as to the commit message that opening/closing /dev/video# from acquire()/release() as done by the uvcvideo pipeline handler is an exception and that this behavior should not be copied by other pipeline handlers - Other doxygen doc fixes / improvements - Only unlock media devices on acquireDevice() failure if useCount_ == 0 --- include/libcamera/internal/pipeline_handler.h | 3 +- src/libcamera/camera.cpp | 2 +- src/libcamera/pipeline_handler.cpp | 48 +++++++++++++++---- 3 files changed, 43 insertions(+), 10 deletions(-) diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h index cad5812f..597f7c3e 100644 --- a/include/libcamera/internal/pipeline_handler.h +++ b/include/libcamera/internal/pipeline_handler.h @@ -45,7 +45,7 @@ public: MediaDevice *acquireMediaDevice(DeviceEnumerator *enumerator, const DeviceMatch &dm); - bool acquire(); + bool acquire(Camera *camera); void release(Camera *camera); virtual std::unique_ptr generateConfiguration(Camera *camera, @@ -79,6 +79,7 @@ protected: virtual int queueRequestDevice(Camera *camera, Request *request) = 0; virtual void stopDevice(Camera *camera) = 0; + virtual bool acquireDevice(Camera *camera); virtual void releaseDevice(Camera *camera); CameraManager *manager_; diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp index 382a68f7..4e393f89 100644 --- a/src/libcamera/camera.cpp +++ b/src/libcamera/camera.cpp @@ -995,7 +995,7 @@ int Camera::acquire() if (ret < 0) return ret == -EACCES ? -EBUSY : ret; - if (!d->pipe_->acquire()) { + if (!d->pipe_->acquire(this)) { LOG(Camera, Info) << "Pipeline handler in use by another process"; return -EBUSY; diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp index 1fc22d6a..861815cb 100644 --- a/src/libcamera/pipeline_handler.cpp +++ b/src/libcamera/pipeline_handler.cpp @@ -163,20 +163,24 @@ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator, * has already acquired it * \sa release() */ -bool PipelineHandler::acquire() +bool PipelineHandler::acquire(Camera *camera) { MutexLocker locker(lock_); - if (useCount_) { - ++useCount_; - return true; + if (useCount_ == 0) { + for (std::shared_ptr &media : mediaDevices_) { + if (!media->lock()) { + unlockMediaDevices(); + return false; + } + } } - for (std::shared_ptr &media : mediaDevices_) { - if (!media->lock()) { + if (!acquireDevice(camera)) { + if (useCount_ == 0) unlockMediaDevices(); - return false; - } + + return false; } ++useCount_; @@ -213,12 +217,40 @@ void PipelineHandler::release(Camera *camera) --useCount_; } +/** + * \brief Acquire resources associated with this camera + * \param[in] camera The camera for which to acquire resources + * + * Pipeline handlers may override this in order to get resources such as opening + * devices and allocating buffers when a camera is acquired. + * + * This is used by the uvcvideo pipeline handler to delay opening /dev/video# + * until the camera is acquired to avoid excess power consumption. The delayed + * opening of /dev/video# is a special case because the kernel uvcvideo driver + * powers on the USB device as soon as /dev/video# is opened. This behavior + * should *not* be copied by other pipeline handlers. + * + * \return True on success, false on failure + * \sa releaseDevice() + */ +bool PipelineHandler::acquireDevice([[maybe_unused]] Camera *camera) +{ + return true; +} + /** * \brief Release resources associated with this camera * \param[in] camera The camera for which to release resources * * Pipeline handlers may override this in order to perform cleanup operations * when a camera is released, such as freeing memory. + * + * This is called once for every camera that is released. If there are resources + * shared by multiple cameras then the pipeline handler must take care to not + * release them until releaseDevice() has been called for all previously + * acquired cameras. + * + * \sa acquireDevice() */ void PipelineHandler::releaseDevice([[maybe_unused]] Camera *camera) {