From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 58E4E314D1F for ; Mon, 21 Sep 2026 11:52:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789991569; cv=none; b=q4Z6kGisrRIXxabvCzNVfAUef9AB0GMBa9PttLvbymATEldXEQrIf4uzp1eGMXlJCow+RM3KKJ+4H6ctmdOHs/LPmeE1ft5gnWGF0cvzIMe6ne8283wYPtajetIMzSbOfJVv2R9zKBYV6zDeFx+blTaLeOMLNgvVbsmDBCMRB+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789991569; c=relaxed/simple; bh=m6bfsH1PTtGg5+RCO8ZPFwn7hrHmGJ0UIfClhvC1u9U=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VyCfmWfSabac2UBU5sb6NC50SvmvmlAn/TgrB+5efxH3hU22U6O2zzaZT081IlfGprlX+/AHUHqO+tDzlacjX4ta0MVq96agjZLNup6uqrAdjtSfXu4S0Slk34KXyeR/FrLjcv9G++7tL570HNajvCZVrWtgbrZUzcTm0W5az7U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D2uuYBN1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D2uuYBN1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2127C1F000FF; Mon, 21 Sep 2026 11:52:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789991567; bh=vt4qmFlVtfpKqJXvGGK4OzlPvlTvPcZDz2S/Ir+JGoc=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=D2uuYBN16xPA4utaoYAtRlhDjSS8KkNTY4xkRazKqAi1NrmBi3PEl9lIgl9xNEXW5 7F583qNt2ayklEYv+ETAm2GxerkXhSfmFOTxgQ3JIUZqLWthxeevdYb8dDZxaX/AA6 SPpisBzNrjPRAGshgggh3xUqWqVfy9d97sPr5EYjXlEbzbz05beCZqbp+8Dx9cBBJh lbFy5SWVDNJQvhMHOwfZbjpV0tCEXs1p1ekGTcuXlWgy2bml2naO37VpWGNrSTbvC7 cHc1R3xQesX6o3hUNzQ1dIaevyrgQnmvzPbSJ+mevFL3mPebRQEod08Ztc6tsGYrxu elKWoI0dIuKWg== Message-ID: <90afd37d-ea90-42ac-8d8c-7b8a30375228@kernel.org> Date: Mon, 21 Sep 2026 12:52:45 +0100 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [ANNOUNCEMENT] Camera & ISP at Linux Plumbers Conference To: Laurent Pinchart Cc: libcamera-devel@lists.libcamera.org, linux-media@vger.kernel.org References: <20260914233810.GA2796257@killaraus.ideasonboard.com> <00cc46b2-0729-46d3-8e3b-ea717ec1675e@kernel.org> <20260918091806.GE59058@killaraus.ideasonboard.com> <20260919222915.GB1179126@killaraus.ideasonboard.com> From: Bryan O'Donoghue Content-Language: en-GB Autocrypt: addr=bod@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 19/09/2026 23:29, Laurent Pinchart wrote: >> V4L2 owning sensor -> inline engine is already supported and won't >> change. For subsequent steps though each stage hands off in-kernel >> without having to involve userspace. > That's fences, isn't it ? Perhaps fences in v4l will do exactly the job I want. I'm more investigating than specifically pushing a solution. My understanding of drm benefits are: - drm_sched job scheduling based on dependency fences - dma_resv fencing, sync - syncobj user-space sync primitives which can be shared with say a compositor - TDR Builtin fault tolerance. Probably the best thing to do is to implement both a v4l and drm wrapper around the functionality and use it in anger. There'd be no specific barrier to implementing a libcamera pipeline around a DRM device, I mean that's what gpuisp is even if its wrappered up in mesa so.. :) Nicolas mentioned the idea of implementing codec drivers in DRM for reasons similar to the above. Anyway I'm curious to know what the DRM advocates and detractors would say about that. It's a question I have not an assertion. For an inline ISP where you connect a sensor to a CSI block the media-graph seems like a nice well defined thing. The offline ISP I'm describing - truthfully has elements of codec and elements of ISP. Probably the only way to really know is to experiment and see what falls out. --- bod