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 29E0538FEE7; Tue, 13 Jan 2026 12:43:17 +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=1768308199; cv=none; b=iK4fQWBMqNbtQOAkBwxdB6QQRrtXii6SPTJcFMrpnEIfLVoQIOfj4zLjm4ibDW1XKl0+ERe8o6XZCgkobmGCzv7ib8IkUZflhHZ0xlUSe22RDCk6EMF2NSB8n+3Td49II9imJ+Y08CcbHXTJcWYOPaXZD8hGDCzrxeK+ySGAJFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768308199; c=relaxed/simple; bh=KYV8YUs5/Ts/mDUYvEvjy/TQD/MsX71OSRUwlnJyqyA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uqW+D+xvA7a6SKiSk6X5h0t8WiNbx1ZOajRGYehUVcZ5WQbEu9kos9twCqd+CXovo4VqE+FgXHnnsbLBRqgOVOQhdWITGvf/8Pkw6Wvr1Kmvi28AAqSqZBN9fLnnkqaXVpp1P4Sd2VDZGWFeOeMACWKi4CzeDQc9VODkHtYWSjI= 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=MvoQjfoM; 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="MvoQjfoM" Received: from ideasonboard.com (net-93-65-100-155.cust.vodafonedsl.it [93.65.100.155]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id A6B0D50A; Tue, 13 Jan 2026 13:42:49 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1768308169; bh=KYV8YUs5/Ts/mDUYvEvjy/TQD/MsX71OSRUwlnJyqyA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MvoQjfoMAuW42PrbiPmd5ZYWUxT6Gyn6/bVatkUXrnjNeO9JH7btqh09ItPAuCBn8 ZI41nMZB02+dNIXiEr06ztnzg4bXbNNNumY4zS/P/9LHPEgAar1sfyfbJfDzc0g/8T scDF7AABrY3Qf3MsB2Wf+v1OXY4hUFm9L/BZSLDo= Date: Tue, 13 Jan 2026 13:43:12 +0100 From: Jacopo Mondi To: Sakari Ailus Cc: Jacopo Mondi , "jempty.liang" , Laurent Pinchart , dan.scally@ideasonboard.com, mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device Message-ID: References: <20260113075722.143238-1-imntjempty@163.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Hi Sakari On Tue, Jan 13, 2026 at 12:40:25PM +0200, Sakari Ailus wrote: > Hi Jacopo, > > On Tue, Jan 13, 2026 at 09:55:10AM +0100, Jacopo Mondi wrote: > > I wonder if v4l2_device_register_subdev() shouldn't WARN or if return > > an error if sd->dev is not initialized. Laurent, Sakari: opinions ? > > I might even return an error but I wonder what would break. Perhaps indeed > could start with a warning? I would start with: --- a/drivers/media/v4l2-core/v4l2-device.c +++ b/drivers/media/v4l2-core/v4l2-device.c @@ -117,6 +117,13 @@ int __v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0]) return -EINVAL; + /* + * Initializing sd->dev is mandatory. Warn for now to give faulty + * drivers a bit of time to update before actually returning an error. + */ + WARN_ON(!sd->dev); + /* * The reason to acquire the module here is to avoid unloading * a module of sub-device which is registered to a media Would you like a patch ? > > -- > Sakari Ailus