[{"id":22256,"web_url":"https://patchwork.libcamera.org/comment/22256/","msgid":"","date":"2022-03-10T10:59:50","subject":"Re: [libcamera-devel] [PATCH v1 6/6] libcamera: v4l2_videodevice:\n\tEmpty the V4L2 buffer cache on streamOff()","submitter":{"id":97,"url":"https://patchwork.libcamera.org/api/people/97/","name":"Nicolas Dufresne via libcamera-devel","email":"libcamera-devel@lists.libcamera.org"},"content":"Hi Naush\n\nThanks for this patch!\n\nOn Mon, 7 Mar 2022 at 12:46, Naushir Patuck via libcamera-devel\n wrote:\n>\n> When streamOff() is called, ensure the cache entires for the remaining queued\n> buffers are freed since this will not happen via the dequeueBuffer() mechanism.\n>\n> Additionally, add a V4L2BufferCache::isEmpty() function and assert that the\n> cache is empty at the end of the streamOff() call.\n>\n> Signed-off-by: Naushir Patuck \n> ---\n> include/libcamera/internal/v4l2_videodevice.h | 1 +\n> src/libcamera/v4l2_videodevice.cpp | 16 ++++++++++++++++\n> 2 files changed, 17 insertions(+)\n>\n> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h\n> index 2d2ccc477c91..37747c0b2f27 100644\n> --- a/include/libcamera/internal/v4l2_videodevice.h\n> +++ b/include/libcamera/internal/v4l2_videodevice.h\n> @@ -126,6 +126,7 @@ public:\n>\n> int get(const FrameBuffer &buffer);\n> void put(unsigned int index);\n> + bool isEmpty() const;\n>\n> private:\n> class Entry\n> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp\n> index 5f36ee20710d..9da82697e7f0 100644\n> --- a/src/libcamera/v4l2_videodevice.cpp\n> +++ b/src/libcamera/v4l2_videodevice.cpp\n> @@ -262,6 +262,19 @@ void V4L2BufferCache::put(unsigned int index)\n> cache_[index].free_ = true;\n> }\n>\n> +/**\n> + * \\brief Check if all the entries in the cache are unused\n> + */\n> +bool V4L2BufferCache::isEmpty() const\n> +{\n> + for (auto const &entry : cache_) {\n> + if (!entry.free_)\n> + return false;\n> + }\n> +\n> + return true;\n> +}\n> +\n> V4L2BufferCache::Entry::Entry()\n> : free_(true), lastUsed_(0)\n> {\n> @@ -1832,10 +1845,13 @@ int V4L2VideoDevice::streamOff()\n> for (auto it : queuedBuffers_) {\n> FrameBuffer *buffer = it.second;\n>\n> + cache_->put(it.first);\n> buffer->metadata_.status = FrameMetadata::FrameCancelled;\n> bufferReady.emit(buffer);\n> }\n>\n> + ASSERT(cache_->isEmpty());\n> +\n> queuedBuffers_.clear();\n> fdBufferNotifier_->setEnabled(false);\n> streaming_ = false;\n> --\n> 2.25.1\n>\n\nNot sure I'm entirely qualified to give a very strong opinion on the\ncorrectness of this, but nonetheless we've been using it for some time\nso:\n\nTested-by: David Plowman \n\nThanks!\nDavid","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 0CAF1BE08A\n\tfor ;\n\tThu, 10 Mar 2022 11:00:04 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 6ED5E632E6;\n\tThu, 10 Mar 2022 12:00:03 +0100 (CET)","from mail-wm1-x32c.google.com (mail-wm1-x32c.google.com\n\t[IPv6:2a00:1450:4864:20::32c])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id DE15C601F8\n\tfor ;\n\tThu, 10 Mar 2022 12:00:01 +0100 (CET)","by mail-wm1-x32c.google.com with SMTP id q20so3005129wmq.1\n\tfor ;\n\tThu, 10 Mar 2022 03:00:01 -0800 (PST)"],"DKIM-Signature":["v=1; 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charset=\"UTF-8\"","Subject":"Re: [libcamera-devel] [PATCH v1 6/6] libcamera: v4l2_videodevice:\n\tEmpty the V4L2 buffer cache on streamOff()","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","From":"David Plowman via libcamera-devel ","Reply-To":"David Plowman ","Cc":"libcamera devel ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]