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 2AC68C4321E for ; Thu, 24 Nov 2022 11:30:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230114AbiKXLai (ORCPT ); Thu, 24 Nov 2022 06:30:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229770AbiKXLaf (ORCPT ); Thu, 24 Nov 2022 06:30:35 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65072BF52; Thu, 24 Nov 2022 03:30:33 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id F136A496; Thu, 24 Nov 2022 12:30:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1669289431; bh=6iBaI/QCGoo2ZY32zk5Z6cIBXzXMw3aWSd+M5LBjEro=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hDoOGVB9NV/+PAaVf6hnJ3gmE64oNM0totgTZe2GeQCKZshBs217M279RbgCpXq/M M8VKPO/ZwyrrPPgxuMJ0b0Nt7EIBlSNngDZhAw4aLU3ZtDOjxt+4/GYpIaYy1e+vft xdPGIncIclM3C/judVqykvC5qA2N1Q1HpdOGOFGg= Date: Thu, 24 Nov 2022 13:30:15 +0200 From: Laurent Pinchart To: Dorota Czaplejewicz Cc: Steve Longerbeam , Philipp Zabel , Mauro Carvalho Chehab , Greg Kroah-Hartman , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , linux-media@vger.kernel.org, linux-staging@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel@puri.sm, phone-devel@vger.kernel.org Subject: Re: [PATCHv3 1/1 RESEND] media: imx: Round line size to 4 bytes Message-ID: References: <20221016163928.1ef0a4fe.dorota.czaplejewicz@puri.sm> <20221017163059.377ac677.dorota.czaplejewicz@puri.sm> <20221101133834.0c1a20db.dorota.czaplejewicz@puri.sm> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20221101133834.0c1a20db.dorota.czaplejewicz@puri.sm> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dorota, On Tue, Nov 01, 2022 at 01:38:34PM +0100, Dorota Czaplejewicz wrote: > On Mon, 17 Oct 2022 16:30:59 +0200 Dorota Czaplejewicz wrote: > > On Mon, 17 Oct 2022 11:28:57 +0300 Laurent Pinchart wrote: > > [snip] > > > > I would also very much appreciate feedback from NXP on this. There's a > > > risk of ill side-effects that I would prefer ruling out very clearly. > > > > I posted a question on the NXP forum: https://community.nxp.com/t5/i-MX-Processors/i-MX8MQ-CSI-line-size-constraint-documentation-mistake/m-p/1538629#M196448 > > > > This question received a reply from NXP today: https://community.nxp.com/t5/i-MX-Processors/i-MX8MQ-CSI-line-size-constraint-documentation-mistake/m-p/1546872/highlight/true#M197067 > > Quoting NXP's answer: > > > Do I understand correctly, that streams divisible by 4×4 will work on other i.MX8 hardware too? - Yes > > Will those kind of resolutions work on i.MX7 series CSI hardware? - Yes > > which implies no bad side effects the way I read it. Is this > sufficient for the kernel? Ideally I'd like to test that on i.MX7 but I don't think I'll have time to do so in the near future. I don't want to block the patch on this, so I'm fine merging it, but I'd like a comment in the code that explains why it's safe to depart from the documentation. Also, the discussion on the NXP forum said that a width that is a multiple of 4 bytes but not a multiple of 8 bytes works only if the height is also a multiple of 4. I don't see that constraint being enforced in the code, am I missing something ? You mentioned in the forum that you tried 1052x779 and that failed. How did it fail ? Have you also tried 1052x778 ? > > > > Signed-off-by: Dorota Czaplejewicz > > > > --- > > > > Hello, > > > > > > > > the Librem 5 is using an out-of-tree driver for s5k3l6xx, and > > > > rounding to 4 is optimal to operate it. > > > > > > > > This revision improves the commit message. > > > > > > > > Cheers, > > > > Dorota Czaplejewicz > > > > > > > > drivers/staging/media/imx/imx7-media-csi.c | 4 ++-- > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/drivers/staging/media/imx/imx7-media-csi.c b/drivers/staging/media/imx/imx7-media-csi.c > > > > index a0553c24cce4..af821b410c3f 100644 > > > > --- a/drivers/staging/media/imx/imx7-media-csi.c > > > > +++ b/drivers/staging/media/imx/imx7-media-csi.c > > > > @@ -999,10 +999,10 @@ static int imx7_csi_mbus_fmt_to_pix_fmt(struct v4l2_pix_format *pix, > > > > } > > > > > > > > /* Round up width for minimum burst size */ > > > > - width = round_up(mbus->width, 8); > > > > + width = round_up(mbus->width, 4); > > > > > > > > /* Round up stride for IDMAC line start address alignment */ > > > > - stride = round_up((width * cc->bpp) >> 3, 8); > > > > + stride = round_up((width * cc->bpp) >> 3, 4); > > > > > > > > pix->width = width; > > > > pix->height = mbus->height; -- Regards, Laurent Pinchart