From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8262A61FF2; Thu, 1 Aug 2024 13:44:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.44 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722519848; cv=none; b=bClMaSKgZJrlnvmQX1ucID0jL1oayIkTRRXcbSDggrm2HEwOeuF6rD3MmuqzPr17j90qk/NazEFvK5TpbkJnrsRnjumdDtnrbd7B8M72eK4sVa7y2mL+YZVlvbjglYcWIumzuDA1SsaxKCNsm1BkBobMoePq1eYZ3eIXkaSn9nA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722519848; c=relaxed/simple; bh=thFxg8OzzcxQf4MMkIWf1lfjmAKKVKW6trC0V+uF7Dw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j3ebfXkzGPMGDApPhrh6PspcQfv2lHf48D6SCWuyBjajK7MPgak+xwM+yEW9Es8W5fPNQ42MvekC3AktLyiOHRJkZrZkVNX2AFQ+P158Q2OQk5kutVgphmErJtldbaLDbNKgQAUS1ngJPGHow8+UyXzSDi3e110q/U0tvci4cuY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=lUCYuuhE; arc=none smtp.client-ip=209.85.208.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lUCYuuhE" Received: by mail-ed1-f44.google.com with SMTP id 4fb4d7f45d1cf-5a156557029so11151224a12.2; Thu, 01 Aug 2024 06:44:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722519845; x=1723124645; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=X88/CsdmLmbELcktNgy2HM0ZWdZzSy/cvXSHWDa5C9w=; b=lUCYuuhEIP6x+2OyTUxdJ3JVIUC2k/RRuMtwqPDM48SeQbr4BdMFg8NPc7PAHU5rrg 2MM1AJQ+ELF9bub3U29X8UJvHtlbRp+cNE54WJcdEX3dWby2rH34tNSIOxObgrK3uao1 iiKHxaMwkAemXfQ3DmKYTrJIPCViJzhbtRvjytfSVINcoBa6HgPCD+IUgGCxOk+gB4Dx lEGdLUv/zfSGnzch7DryhZ35wIpFb21Y/MrUZ28ZVofp+j5THPDIR5NC6pQuqhKeoTo2 oHEAf/sHNDspi7/hddEQguitsVL8AMHhGJupJ8z11p4L4dD/RFoY4P4CZVxMO3uVx4IM GxUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722519845; x=1723124645; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=X88/CsdmLmbELcktNgy2HM0ZWdZzSy/cvXSHWDa5C9w=; b=lPUoVQY4WLJwpH2P4sJDh0Y1u02q70DDGezgl+9JuSfNLyW4DoJLdqkArSwgtu9Xc/ ZbuDYZ+a6J5f/KkdmW+7fQp5esyo/dbbGCqmTdzHca3LW63l/wM28bXCem2/TtD2Ysyk SFuQ9g13mFOl2pNHuJWWf4cTzY+OHTCH2qWCr67V0i91ZTA2v/UScZpsw6iZ81tln6Gh U/BNPsIHvKoKH4Rsu3/Iuz9x3hu7V3jWIbMOXD+MW3Lo94RzpJdJ0t23lu6gWlqjjnvJ 4o8FR5pqZVvf3EZVRm1rpJlrdADfgfUdzGzZysSCBgpyTo1kFQXu4doTJ4an4DjPKlr0 Z8vQ== X-Forwarded-Encrypted: i=1; AJvYcCVPw40BQRN4uL6zHI5ZPYxYlgJ4A0VzRLk10FzQUyKZQOqiu+npTtoXDZGxMAaxn4/2ewS8jGpIJJKYrVc5VmbUdKNLcLKu X-Gm-Message-State: AOJu0YxqIEDTVvDpYPzeEGUmLBMEE6TCeFdAvSyA22JEa2CaSLSYErA8 hUSa1yJQ7Rl6A2eXEnYctQ1/uEGQ3xj/vePiNZ8Qbm2W+24E/yzA X-Google-Smtp-Source: AGHT+IGFNv2QHGvPS9i2SZVHutTLhDALDLT5CL38a93ykAR/jj7dmB+landsIUaymqtGa8TIH7UKPw== X-Received: by 2002:aa7:d552:0:b0:5a3:f5c6:7cd5 with SMTP id 4fb4d7f45d1cf-5b7f550a75cmr238198a12.26.1722519844469; Thu, 01 Aug 2024 06:44:04 -0700 (PDT) Received: from skbuf ([188.25.135.70]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5ac65783665sm9979717a12.94.2024.08.01.06.44.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Aug 2024 06:44:03 -0700 (PDT) Date: Thu, 1 Aug 2024 16:44:01 +0300 From: Vladimir Oltean To: vtpieter@gmail.com Cc: devicetree@vger.kernel.org, woojung.huh@microchip.com, UNGLinuxDriver@microchip.com, netdev@vger.kernel.org, o.rempel@pengutronix.de, Pieter Van Trappen , Florian Fainelli , Andrew Lunn Subject: Re: [PATCH net-next 0/2] implement microchip,no-tag-protocol flag Message-ID: <20240801134401.h24ikzuoiakwg4i4@skbuf> References: <20240801123143.622037-1-vtpieter@gmail.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-Disposition: inline In-Reply-To: <20240801123143.622037-1-vtpieter@gmail.com> Hi Pieter, On Thu, Aug 01, 2024 at 02:31:41PM +0200, vtpieter@gmail.com wrote: > From: Pieter Van Trappen > > Add and implement microchip,no-tag-protocol flag to allow disabling > the switch' tagging protocol. For cases where the CPU MAC does not > support MTU size > 1500 such as the Zynq GEM. > > This code was tested with a KSZ8794 chip. > > Pieter Van Trappen (2): > dt-bindings: net: dsa: microchip: add microchip,no-tag-protocol flag > net: dsa: microchip: implement microchip,no-tag-protocol flag > > .../devicetree/bindings/net/dsa/microchip,ksz.yaml | 5 +++++ > drivers/net/dsa/microchip/ksz8795.c | 2 +- > drivers/net/dsa/microchip/ksz9477.c | 2 +- > drivers/net/dsa/microchip/ksz_common.c | 11 ++++++++--- > drivers/net/dsa/microchip/ksz_common.h | 1 + > drivers/net/dsa/microchip/lan937x_main.c | 2 +- > 6 files changed, 17 insertions(+), 6 deletions(-) > > > base-commit: 0a658d088cc63745528cf0ec8a2c2df0f37742d9 > -- > 2.43.0 Please use ./scripts/get_maintainer.pl when generating the To: and Cc: fields. Not to say that they don't exist, but I have never seen a NIC where MTU=1500 is the absolute hard upper limit. How seriously did you study this before determining that it is impossible to raise that? We're talking about one byte for the tail tag, FWIW. There are also alternative paths to explore, like reducing the DSA user ports MTU to 1499. This is currently not done when dev_set_mtu() fails on the conduit, because Andrew said in the past it's likelier that the conduit is coded to accept up to 1500 but will still work for small oversized packets. Disabling DSA tagging is a very heavy hammer, because it cuts off a whole lot of functionality (the driver should no longer accept PTP hwtimestamping ioctls, etc), so the patch set gets this tag from me currently, due to very shallow justification: Nacked-by: Vladimir Oltean Please carry it forward if you choose to resubmit. Even assuming that a strong justification does exists, there already exists a mechanism for disabling the tagging protocol from the device tree. It is the same as for specifying any other alternative tagging protocol (applied in this case to DSA_TAG_PROTO_NONE). ethernet-switch@N { dsa-tag-protocol = "none"; }; it just needs implementing in the driver. The fact that you chose to add a custom device tree property suggests to me that you did not investigate the problem space very seriously.