[{"id":17497,"web_url":"https://patchwork.libcamera.org/comment/17497/","msgid":"<20210609171004.jzsbyesavd75yem2@uno.localdomain>","date":"2021-06-09T17:10:04","subject":"Re: [libcamera-devel] [PATCH v6 1/5] libcamera: camera: Make stop()\n\tidempotent","submitter":{"id":3,"url":"https://patchwork.libcamera.org/api/people/3/","name":"Jacopo Mondi","email":"jacopo@jmondi.org"},"content":"Hi Nicolas,\n\nOn Mon, Jun 07, 2021 at 03:15:02PM -0300, Nícolas F. R. A. Prado wrote:\n> Make Camera::stop() idempotent so that it can be called in any state and\n> consecutive times. When called in any state other than CameraRunning, it\n> is a no-op. This simplifies the cleanup path for applications.\n>\n> Signed-off-by: Nícolas F. R. A. Prado \n> Reviewed-by: Laurent Pinchart \n\nStill not in love with this one :)\nI guess now that you're moving to use gtest it's even harder to stop\nthe camera at the right time, so\n\nReviewed-by: Jacopo Mondi \n\nThanks\n j\n> ---\n> No changes in v6\n>\n> Changes in v5:\n> - Thanks to Laurent:\n> - Simplified isRunning()\n>\n> Changes in v4:\n> - Thanks to Jacopo:\n> - Added \\todo in Camera::stop()\n>\n> No changes in v3\n>\n> Changes in v2:\n> - Suggested by Kieran:\n> - Add new isRunning() function instead of relying on isAccessAllowed()\n> - Suggested by Laurent:\n> - Make stop()'s description clearer\n>\n> src/libcamera/camera.cpp | 20 +++++++++++++++++---\n> 1 file changed, 17 insertions(+), 3 deletions(-)\n>\n> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp\n> index 1340c266cc5f..a13a15dd1fc9 100644\n> --- a/src/libcamera/camera.cpp\n> +++ b/src/libcamera/camera.cpp\n> @@ -347,6 +347,7 @@ public:\n> \t\tconst std::set &streams);\n> \t~Private();\n>\n> +\tbool isRunning() const;\n> \tint isAccessAllowed(State state, bool allowDisconnected = false,\n> \t\t\t const char *from = __builtin_FUNCTION()) const;\n> \tint isAccessAllowed(State low, State high,\n> @@ -388,6 +389,11 @@ static const char *const camera_state_names[] = {\n> \t\"Running\",\n> };\n>\n> +bool Camera::Private::isRunning() const\n> +{\n> +\treturn state_.load(std::memory_order_acquire) == CameraRunning;\n> +}\n> +\n> int Camera::Private::isAccessAllowed(State state, bool allowDisconnected,\n> \t\t\t\t const char *from) const\n> {\n> @@ -1061,9 +1067,10 @@ int Camera::start(const ControlList *controls)\n> * This method stops capturing and processing requests immediately. All pending\n> * requests are cancelled and complete synchronously in an error state.\n> *\n> - * \\context This function may only be called when the camera is in the Running\n> - * state as defined in \\ref camera_operation, and shall be synchronized by the\n> - * caller with other functions that affect the camera state.\n> + * \\context This function may be called in any camera state as defined in \\ref\n> + * camera_operation, and shall be synchronized by the caller with other\n> + * functions that affect the camera state. If called when the camera isn't\n> + * running, it is a no-op.\n> *\n> * \\return 0 on success or a negative error code otherwise\n> * \\retval -ENODEV The camera has been disconnected from the system\n> @@ -1073,6 +1080,13 @@ int Camera::stop()\n> {\n> \tPrivate *const d = LIBCAMERA_D_PTR();\n>\n> +\t/*\n> +\t * \\todo Make calling stop() when not in 'Running' part of the state\n> +\t * machine rather than take this shortcut\n> +\t */\n> +\tif (!d->isRunning())\n> +\t\treturn 0;\n> +\n> \tint ret = d->isAccessAllowed(Private::CameraRunning);\n> \tif (ret < 0)\n> \t\treturn ret;\n> --\n> 2.31.1\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 68B91BD78E\n\tfor ;\n\tWed, 9 Jun 2021 17:09:16 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 387AB6892F;\n\tWed, 9 Jun 2021 19:09:16 +0200 (CEST)","from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net\n\t[217.70.183.197])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 83BF3602A0\n\tfor ;\n\tWed, 9 Jun 2021 19:09:15 +0200 (CEST)","(Authenticated sender: jacopo@jmondi.org)\n\tby relay5-d.mail.gandi.net (Postfix) with ESMTPSA id A45411C0004;\n\tWed, 9 Jun 2021 17:09:14 +0000 (UTC)"],"Date":"Wed, 9 Jun 2021 19:10:04 +0200","From":"Jacopo Mondi ","To":"=?utf-8?b?TsOtY29sYXMgRi4gUi4gQS4=?= Prado ","Message-ID":"<20210609171004.jzsbyesavd75yem2@uno.localdomain>","References":"<20210607181506.51711-1-nfraprado@collabora.com>\n\t<20210607181506.51711-2-nfraprado@collabora.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20210607181506.51711-2-nfraprado@collabora.com>","Subject":"Re: [libcamera-devel] [PATCH v6 1/5] libcamera: camera: Make stop()\n\tidempotent","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera-devel@lists.libcamera.org, kernel@collabora.com, =?utf-8?q?A?=\n\t=?utf-8?b?bmRyw6k=?= Almeida ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]