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 smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1AA9AC433EF for ; Mon, 17 Jan 2022 23:04:56 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 9872860598; Mon, 17 Jan 2022 23:04:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IxG_lFPW-4xT; Mon, 17 Jan 2022 23:04:55 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by smtp3.osuosl.org (Postfix) with ESMTP id DD475600C6; Mon, 17 Jan 2022 23:04:54 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by ash.osuosl.org (Postfix) with ESMTP id E53D01BF286 for ; Mon, 17 Jan 2022 23:04:53 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id DFEE04038B for ; Mon, 17 Jan 2022 23:04:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GLENu1HBTye7 for ; Mon, 17 Jan 2022 23:04:52 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::223]) by smtp2.osuosl.org (Postfix) with ESMTPS id 9517D40012 for ; Mon, 17 Jan 2022 23:04:52 +0000 (UTC) Received: (Authenticated sender: thomas.petazzoni@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 1AA6D60004; Mon, 17 Jan 2022 23:04:48 +0000 (UTC) Date: Tue, 18 Jan 2022 00:04:48 +0100 From: Thomas Petazzoni To: Giulio Benetti Message-ID: <20220118000448.32ea764d@windsurf> In-Reply-To: <752cc85f-d3d6-950b-cb5c-fb39e5020bc3@benettiengineering.com> References: <20220114211525.2697606-1-heiko.thiery@gmail.com> <752cc85f-d3d6-950b-cb5c-fb39e5020bc3@benettiengineering.com> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Subject: Re: [Buildroot] [PATCH v2] configs/kontron_bl_imx8mm_defconfig: new defconfig X-BeenThere: buildroot@buildroot.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion and development of buildroot List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Heiko Thiery , Fabio Estevam , Frieder Schrempf , buildroot@buildroot.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: buildroot-bounces@buildroot.org Sender: "buildroot" On Mon, 17 Jan 2022 20:58:52 +0100 Giulio Benetti wrote: > > diff --git a/configs/kontron_bl_imx8mm_defconfig b/configs/kontron_bl_imx8mm_defconfig > > new file mode 100644 > > index 0000000000..5b5648cc14 > > --- /dev/null > > +++ b/configs/kontron_bl_imx8mm_defconfig > > @@ -0,0 +1,59 @@ > > +# Architecture > > +BR2_aarch64=y > > +BR2_ARM_FPU_VFPV3=y > > i.MX8MM supports VFPv4-D16, so I would substitute this ^^^ with: > BR2_ARM_FPU_VFPV4D16 > > This is to achieve the maximum performance. Nope, that's not really how it works. VFPv3 is better than VFPv3-D16. Indeed VFPv3 means that the the FPU has 32 double precision registers, while VFPv3-D16 means that it has "only" 16 double precision registers. So, if the i.MX8MM has only the VFPv3-D16, then indeed it should be chosen, because code compiled with VFPv3 may not work, as it might use too many double precision registers. On the other hand, if the i.MX8MM has the full VFPv3, then BR2_ARM_FPU_VFPV3=y should be used. That being said, the gcc man page only documents vfpv3, vfpv3-d16-fp16, vfpv3-fp16 as extension for armv7-a. Interesting, would need to look into this. Best regards, Thomas -- Thomas Petazzoni, co-owner and CEO, Bootlin Embedded Linux and Kernel engineering and training https://bootlin.com _______________________________________________ buildroot mailing list buildroot@buildroot.org https://lists.buildroot.org/mailman/listinfo/buildroot