From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C742C61DA4 for ; Thu, 23 Feb 2023 17:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230257AbjBWRw5 (ORCPT ); Thu, 23 Feb 2023 12:52:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229664AbjBWRw4 (ORCPT ); Thu, 23 Feb 2023 12:52:56 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11F0D977E for ; Thu, 23 Feb 2023 09:52:53 -0800 (PST) Received: from [192.168.1.15] (91-154-32-225.elisa-laajakaista.fi [91.154.32.225]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 3F234496; Thu, 23 Feb 2023 18:52:51 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1677174771; bh=a3wY6sx7vT/o9eAy+p4i2b8eWYJNzDeo4ODWAdagOWk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=GNLALscNbN+OtXXYz/TVZYQ4IANs0YbMUlT04F4DQbmD3Qb18J+hEBueWJlUes0Qw w2n1QT1ocVNvyAZ5ZIBb7FqBU4AN1Z1WvSmrYk7IDNwLDr4JJJwzUfB83XoO5C6XPh SPE+T5KPCn+DqZbDeS6dueiRe8rjBbsdR0h1RhzM= Message-ID: Date: Thu, 23 Feb 2023 19:52:48 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v1 1/3] media: ti: cal: Add support for 1X16 mbus formats Content-Language: en-US To: Jacopo Mondi Cc: linux-media@vger.kernel.org, Laurent Pinchart , Sakari Ailus , Kieran Bingham , Jai Luthra , Vaishnav Achath References: <20230222125630.421020-1-tomi.valkeinen@ideasonboard.com> <20230222125630.421020-2-tomi.valkeinen@ideasonboard.com> <20230223171021.ukttr2xwcuxlzdzu@uno.localdomain> From: Tomi Valkeinen In-Reply-To: <20230223171021.ukttr2xwcuxlzdzu@uno.localdomain> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 23/02/2023 19:10, Jacopo Mondi wrote: > Hi Tomi > > On Wed, Feb 22, 2023 at 02:56:28PM +0200, Tomi Valkeinen wrote: >> For legacy reasons the CAL driver uses 2X8 mbus formats for the CSI-2 >> link (e.g. MEDIA_BUS_FMT_YUYV8_2X8). 1X16 formats are more correct and >> used by many drivers, so add 1X16 support to CAL. >> >> We keep the 2X8 formats for backward compatibility. > > Eh, this is the usual question about what we should consider a > to be a userspace breakage or not. > > I presume the reason to maintain 2X8 formats is (assuming the CAL > interface is CSI-2 only, right ?) because sensor drivers that only > support 2X8 formats will then fail to link_validate() if you remove Yes. > all 2X8 formats here. I'm of the opinion that we should bite the > bullet and move to 1X16. If any driver that used to work with CAL now > breaks, the sensor driver will have to be fixed. > > In my humble experience, that's what we did with the ov5640 sensor. We Yes, you did. > removed the 2X8 formats in CSI-2 mode and some platform driver broke > and then had been fixed (it happened in the same release cycle), win win. No, CAL is still broken =). OV5640 is the only sensor I have. I just haven't had time to look at this and fix it (and no one has complained). > I know it's controversial, let's see what others think. I'm all for dropping the 2X8 formats, if that's the consensus. It would keep the driver simpler, as we could keep the 1:1 relationship between pixel formats and mbus codes. I'll look at your other comments tomorrow. Tomi