From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 01AA1A2D; Tue, 18 Jun 2024 00:08:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718669281; cv=none; b=oS4gNyt+v3qZx7bP+ehvoG2g34Glo3t7ge8C22jylYLBjcLY6X7O/ycACfIJwhObVnfsdX0k2Wee1oyDjP++j/kEh+V0Jj8T0yx4jb5N7qvD1wPRYd1ierneY0P5yIrbHcn9IFSJey7ttt/xYNmMaQrbZWSWppi91lzajSCIOx4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718669281; c=relaxed/simple; bh=36CWnSggwu9XEgK+BEW2dfoLh8Wx1BkoZxBKpSE9AnU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DCB0EY/eKGMybx2MT50lDSXB/7IpNRqqyZqLDsNhzpHy3SnNrPW3bKOyt/IrkqR/AuAiLE+nkvT3M80PIeThY5wzrY1UpKElCzMYVwKdq5ORZ6olZ5EBPjY+N9BwuJZ0XCvIoP2tziQpHESwdA2PNhpEuuvorkcjATCCHE+QrVo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VhfnAN3j; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VhfnAN3j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 332D4C2BD10; Tue, 18 Jun 2024 00:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718669280; bh=36CWnSggwu9XEgK+BEW2dfoLh8Wx1BkoZxBKpSE9AnU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VhfnAN3jYTWFr8q1guxkDQZQanRe3Z5Dtz9Akt8z35c7726VUAR34bxW2eNrZZA76 y2Yu+4A5MZbvkX5TtCNcH/L14PpuL58mOJsIiVAkTIThGPHzG5p6c4G6ZHQUP92uoa RwtHKCgiu4BUBNUEtbZyC5I10jm6BohMcAPD5W5bxYjviSfrULY4Esr/snW6B0uoSK 7NXjSa+FRRh7OuYbK6m9DWFLCF7+4RqITigw6E8h3hINH/yxMNv5EaKIHhdOjEMwd2 cOONREvLbO+4pBbmr724rrUjbWbaYqRzWaI6ddqN3/ISSxX4ADSUPppzKyEJzzhWh6 cxdpPk4RHW0vA== Date: Mon, 17 Jun 2024 17:07:59 -0700 From: Jakub Kicinski To: Paul Barker Cc: Sergey Shtylyov , "David S. Miller" , Eric Dumazet , Paolo Abeni , Niklas =?UTF-8?B?U8O2ZGVybHVuZA==?= , Biju Das , Claudiu Beznea , Lad Prabhakar , Mitsuhiro Kimura , netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [net-next PATCH 1/2] net: ravb: Fix maximum MTU for GbEth devices Message-ID: <20240617170759.270f79f0@kernel.org> In-Reply-To: <20240615103038.973-2-paul.barker.ct@bp.renesas.com> References: <20240615103038.973-1-paul.barker.ct@bp.renesas.com> <20240615103038.973-2-paul.barker.ct@bp.renesas.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 15 Jun 2024 11:30:37 +0100 Paul Barker wrote: > The datasheets for all SoCs using the GbEth IP specify a maximum > transmission frame size of 1.5 kByte. I've confirmed through internal > discussions that support for 1522 byte frames has been validated, which > allows us to support the default MTU of 1500 bytes after reserving space > for the Ethernet header, frame checksums and an optional VLAN tag. But what's the user impact? If we send a bigger frame the IP will hang? Drop the packet? Something else? "Validated" can also mean "officially supported" sometimes vendors just say that to narrow down the test matrix :(