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 2AFEF3655E7; Tue, 16 Jun 2026 12:35:21 +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=1781613330; cv=none; b=KtDdnAjVl54OUKQTQ+t80Q0CVHyqgReBGwi3v+lKVpXDsJ44QGHgxC/zCIWEDaa6YXrldMgAT4Da+E8VD6XhUNFi4ZCQ1h8dMEe014gAZ6H5ogCWv70RviqPzkzCLZPFzwsohqPbPIVnuGaP0nEVoBAMAp4rnxySvPvUzg5uLu8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781613330; c=relaxed/simple; bh=RYLIqNBdvCgEZwg8Nx8bX+w7fFoQzuxayJSY7iegh8I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XF5uZp7qyPkxWXpUXPRfwUXTKZHB0/TRK/Puu4+5q1Hvmk5JvNsv/hEPghU6Nro1XvbvEkutC5WllvjY30q9jLUZU6D++LJwNoo4cK1WbD2Y9CrxGYsMMB++Ol3BslU9NSVdYHaORQ4/xRcYKf5gXkBIvQXG/0sGsqGYrTqOI1I= 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=E2yVxo42; 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="E2yVxo42" Received: from killaraus.ideasonboard.com (2001-14ba-70f3-e800--a06.rev.dnainternet.fi [IPv6:2001:14ba:70f3:e800::a06]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 53F371E6; Tue, 16 Jun 2026 14:34:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1781613286; bh=RYLIqNBdvCgEZwg8Nx8bX+w7fFoQzuxayJSY7iegh8I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=E2yVxo42TJNUuC8juqMjzZgyAT4krIjWrRm0mMDQJc3Se76eBZPj6Um8ANBsM5Dpl OBOcXTNml2Q+B3d1YLjDq7IMUDEotTCl6GGLeOQpga6cw487G7d93nnTaokYhLn1AJ xjLwA+ef+CxCRwqhv8X4ckAtQVZFhOAwAirYXk4s= Date: Tue, 16 Jun 2026 15:35:18 +0300 From: Laurent Pinchart To: Niklas =?utf-8?Q?S=C3=B6derlund?= Cc: Tomi Valkeinen , Mauro Carvalho Chehab , Sakari Ailus , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Mauro Carvalho Chehab , Jacopo Mondi Subject: Re: [PATCH v5 03/10] media: rcar-csi2: Move {enable|disable}_streams() calls Message-ID: <20260616123518.GE2984510@killaraus.ideasonboard.com> References: <20260311-rcar-streams-v5-0-3e6c957d7567@ideasonboard.com> <20260311-rcar-streams-v5-3-3e6c957d7567@ideasonboard.com> <20260318205435.GG716464@killaraus.ideasonboard.com> <20260404121906.GC1525575@ragnatech.se> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260404121906.GC1525575@ragnatech.se> On Sat, Apr 04, 2026 at 02:19:06PM +0200, Niklas Söderlund wrote: > On 2026-03-18 22:54:35 +0200, Laurent Pinchart wrote: > > On Wed, Mar 11, 2026 at 03:53:16PM +0200, Tomi Valkeinen wrote: > > > With multiple streams the operation to enable the CSI-2 hardware and to > > > call {enable|disable}_streams() on upstream subdev will need to be > > > handled separately. > > > > > > Prepare for that by moving {enable|disable}_streams() calls out from > > > rcsi2_start() and rcsi2_stop(). > > > > > > On Gen3, a side effect of this change is that if the sink side devices > > > call .enable_streams() on rcar-csi2 multiple times, the second call will > > > fail. This is because we always use stream ID 0, so the second call > > > would attempt to enable the same stream again, leading to an error. In > > > other words, a normal single-stream setup continues to work, but trying > > > to use the current driver's custom VC based routing will fail. > > > > I assume this gets addressed later in the series. > > > > > > > > On Gen4, this doesn't matter as the rcar-isp behaves in a similar way as > > > described above, and thus rcar-csi2 will only get a single > > > .enable_streams() call. > > > > > > Signed-off-by: Tomi Valkeinen > > > --- > > > drivers/media/platform/renesas/rcar-csi2.c | 25 +++++++++++++++---------- > > > 1 file changed, 15 insertions(+), 10 deletions(-) > > > > > > diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c > > > index 7305cc4a04cb..158fa447e668 100644 > > > --- a/drivers/media/platform/renesas/rcar-csi2.c > > > +++ b/drivers/media/platform/renesas/rcar-csi2.c > > > @@ -1822,20 +1822,12 @@ static int rcsi2_start(struct rcar_csi2 *priv, struct v4l2_subdev_state *state) > > > return ret; > > > } > > > > > > - ret = v4l2_subdev_enable_streams(priv->remote, priv->remote_pad, > > > - BIT_ULL(0)); > > > - if (ret) { > > > - rcsi2_enter_standby(priv); > > > - return ret; > > > - } > > > - > > > return 0; > > > } > > > > > > static void rcsi2_stop(struct rcar_csi2 *priv) > > > { > > > rcsi2_enter_standby(priv); > > > - v4l2_subdev_disable_streams(priv->remote, priv->remote_pad, BIT_ULL(0)); > > > } > > > > > > static int rcsi2_enable_streams(struct v4l2_subdev *sd, > > > @@ -1857,6 +1849,14 @@ static int rcsi2_enable_streams(struct v4l2_subdev *sd, > > > return ret; > > > } > > > > > > + ret = v4l2_subdev_enable_streams(priv->remote, priv->remote_pad, > > > + BIT_ULL(0)); > > > + if (ret) { > > > + if (priv->stream_count == 0) > > > + rcsi2_stop(priv); > > > + return ret; > > > + } > > > + > > > priv->stream_count += 1; > > > > > > return ret; > > > @@ -1867,7 +1867,7 @@ static int rcsi2_disable_streams(struct v4l2_subdev *sd, > > > u32 source_pad, u64 source_streams_mask) > > > { > > > struct rcar_csi2 *priv = sd_to_csi2(sd); > > > - int ret = 0; > > > + int ret; > > > > > > if (source_streams_mask != 1) > > > return -EINVAL; > > > @@ -1878,9 +1878,14 @@ static int rcsi2_disable_streams(struct v4l2_subdev *sd, > > > if (priv->stream_count == 1) > > > rcsi2_stop(priv); > > > > > > + ret = v4l2_subdev_disable_streams(priv->remote, priv->remote_pad, > > > + BIT_ULL(0)); > > > + if (ret) > > > + return ret; > > > + > > > priv->stream_count -= 1; > > > > > > - return ret; > > > + return 0; > > > } > > > > rcsi2_irq_thread() also calls rcsi2_stop(), followed by rcsi2_start(). > > This is to handle errors reported by the AFIFO_OF, ERRSOTHS and > > ERRSOTSYNCHS interrupts. If the source isn't restarted, such an attempt > > to recover from errors will likely fail. On the other hand, restarting > > the source will likely not lead to great results either. > > > > Error handling was introduced in > > > > commit 4ab44ff0841b9a825f9875623d24809d29e37a10 > > Author: Niklas Söderlund > > Date: Thu Apr 11 16:30:58 2019 -0400 > > > > media: rcar-csi2: restart CSI-2 link if error is detected > > > > Restart the CSI-2 link if the CSI-2 receiver detects an error during > > reception. The driver did nothing when a link error happened and the > > data flow simply stopped without the user knowing why. > > > > Change the driver to try and recover from errors by restarting the link > > and informing the user that something is not right. For obvious reasons > > it's not possible to recover from all errors (video source disconnected > > for example) but in such cases the user is at least informed of the > > error and the same behavior of the stopped data flow is retained. > > > > Niklas, do you recall anything about the errors you saw ? > > IIRC, the spark for the work was a user report where the wish was to > handle detectable errors somehow instead of just silently fail. The > first try was this commit where the driver tries to recover. However as > you point out it might not be the optimal solution. > > Instead I proposed a way to signal to user-space that there where a link > error and let it deal with it [1]. As seen on the date from that work it > kind of stalled. I still plan to resume that work once all the cleanups > of the R-Car VIN pipeline are done. Handling it in userspace seems a good idea to me. > 1. https://lore.kernel.org/linux-renesas-soc/20211108160220.767586-1-niklas.soderlund%2Brenesas@ragnatech.se/ > > > > > > > static int rcsi2_set_pad_format(struct v4l2_subdev *sd, > > > -- Regards, Laurent Pinchart