From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 ABEA239A7E4; Thu, 15 Jan 2026 12:56:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768481789; cv=none; b=lOUnRkORy+67rvKQdq85R09V59QVPhg/u6QYP5aKkS7bEYwfg6wiM6PCCdEr8PShuuMLvmynzOy3L8Ya2P8yEun+dbJZZ6XO0JgyHBBxCB6uYmp/ilSMj+M+MQnRcP41TWJtB83TnWwx1LQSVzPZc1obY63JIiXIfdlMLuGHOaw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768481789; c=relaxed/simple; bh=xBG5kxt01OnDBPEI2cz2ikQBniSf47nJEhU91qbntfE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ey6xwh/fg4Om3KPO3LuAB2t7m0b4ljTRS38fLRq0gMAOdcgZzH7jsYh7+IMcLrRUL3Fd7L2ZzQ4S6EAbnk18usPjNXP395Grf+hTkgZPMTyD6h9l2zuXyasEY107GPx3/jg/5YqS/XS1j4r4+4s/0AYCTPgYupSnU+8V4Lo9q+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=e4ubg4pS; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="e4ubg4pS" Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id C8DA024A; Thu, 15 Jan 2026 13:55:56 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1768481758; bh=xBG5kxt01OnDBPEI2cz2ikQBniSf47nJEhU91qbntfE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=e4ubg4pS4heP1m2hLqHQnSUWtaa1h1cu4DcDLgTFT5L7XevmQ8IlN8iwTLjpXbnHU vj7Gd6pxNCZhRGShF3qwI95WMG8p5tvHubsrQzxBwc1jYrDjoR8BRp39eHQnXFK9N+ hwTdst54RWdApEUU2pWVjfn503IhdJiTBGFKuZKI= Message-ID: Date: Thu, 15 Jan 2026 14:56:21 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 06/19] media: ti: j721e-csi2rx: add a subdev for the core device To: Jai Luthra , Laurent Pinchart , Sakari Ailus Cc: y-abhilashchandra@ti.com, devarsht@ti.com, s-jain1@ti.com, vigneshr@ti.com, mchehab@kernel.org, robh@kernel.org, krzk+dt@kernel.org, p.zabel@pengutronix.de, conor+dt@kernel.org, hverkuil-cisco@xs4all.nl, changhuang.liang@starfivetech.com, jack.zhu@starfivetech.com, sjoerd@collabora.com, dan.carpenter@linaro.org, hverkuil+cisco@kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, jai.luthra@linux.dev, mripard@kernel.org, Rishikesh Donadkar , Laurent Pinchart , Sakari Ailus References: <20251230083220.2405247-1-r-donadkar@ti.com> <20251230083220.2405247-7-r-donadkar@ti.com> <176845899846.9154.18009615769864845946@freya> From: Tomi Valkeinen Content-Language: en-US Autocrypt: addr=tomi.valkeinen@ideasonboard.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 15/01/2026 08:36, Jai Luthra wrote: > Hi Tomi, > > +Sakari, Laurent > > Quoting Tomi Valkeinen (2026-01-14 20:51:49) >> Hi, >> >> On 30/12/2025 10:32, Rishikesh Donadkar wrote: >>> From: Jai Luthra >>> >>> With single stream capture, it was simpler to use the video device as >>> the media entity representing the main TI CSI2RX device. Now with multi >>> stream capture coming into the picture, the model has shifted to each >>> video device having a link to the main device's subdev. The routing >>> would then be set on this subdev. >>> >>> Add this subdev, link each context to this subdev's entity and link the >>> subdev's entity to the source. Also add an array of media pads. It will >>> have one sink pad and source pads equal to the number of contexts. >>> >>> Support the new enable_stream()/disable_stream() APIs in the subdev >>> instead of s_stream() hook. >>> >>> Reviewed-by: Yemike Abhilash Chandra >>> Co-developed-by: Pratyush Yadav >>> Signed-off-by: Pratyush Yadav >>> Signed-off-by: Jai Luthra >>> Signed-off-by: Rishikesh Donadkar >>> --- > > [...] > >>> @@ -981,48 +1138,52 @@ static int ti_csi2rx_link_validate(struct media_link *link) >>> struct ti_csi2rx_ctx *ctx = container_of(vdev, struct ti_csi2rx_ctx, vdev); >>> struct ti_csi2rx_dev *csi = ctx->csi; >>> struct v4l2_pix_format *csi_fmt = &ctx->v_fmt.fmt.pix; >>> - struct v4l2_subdev_format source_fmt = { >>> - .which = V4L2_SUBDEV_FORMAT_ACTIVE, >>> - .pad = link->source->index, >>> - }; >>> + struct v4l2_mbus_framefmt *format; >>> + struct v4l2_subdev_state *state; >>> const struct ti_csi2rx_fmt *ti_fmt; >>> - int ret; >>> >>> - ret = v4l2_subdev_call_state_active(csi->source, pad, >>> - get_fmt, &source_fmt); >>> - if (ret) >>> - return ret; >>> + state = v4l2_subdev_lock_and_get_active_state(&csi->subdev); >>> + format = v4l2_subdev_state_get_format(state, link->source->index, 0); >>> + v4l2_subdev_unlock_state(state); >>> >>> - if (source_fmt.format.width != csi_fmt->width) { >>> + if (!format) { >>> + dev_dbg(csi->dev, >>> + "Skipping validation as no format present on \"%s\":%u:0\n", >>> + link->source->entity->name, link->source->index); >>> + return 0; >> >> Isn't this an error? > > Well, the j7 shim subdev introduced here has immutable and active links to > all the video nodes, for each DMA channel (taken from DT), many of which > may be unused for certain setups, and thus there might not be any valid > format on the subdev source pad corresponding to an unused video node. > > Jacopo had a similar comment on v2, see this discussion (grep for Mali): > https://lore.kernel.org/linux-media/4mnlnsj4co3agvln4qsasmgvgwiyoo7yu2h5wyh4rmzzafhm5u@avhnbw7iknms/ > > I know other drivers use a different approach with mutable links, so it > would be good if you/Laurent/Sakari can give your opinions on if only one > of these two approaches should be taken for multi-stream pipelines. I see. Well, I don't have a definite answer. With some thinking both options make certain sense. It makes sense to keep the links immutable and always enabled, as there's no configuration that can be done. On the other hand, it makes sense to require the unused links to be disabled, as, well, they are not used. Tomi