[From nobody Thu Jun 25 05:54:39 2020 Received: from mail-oi0-x244.google.com ([2607:f8b0:4003:c06::244]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fLuXg-0005NP-VQ for openwrt-devel@lists.openwrt.org; Thu, 24 May 2018 18:00:50 +0000 Received: by mail-oi0-x244.google.com with SMTP id p62-v6so2261081oie.10 for <openwrt-devel@lists.openwrt.org>; Thu, 24 May 2018 11:00:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=mHERE8Ht7Z4ovtjghyF5hK9A/Lo1ZaNeNeJNzV0B+CQ=; b=SBe9KXzLomeQmQZ3doJ1luVnO9f+nD4girz6fl8j8mc6lJSrOj9uz/c3r9hxP/RXEB OF5aWZ5LbaJdyFeByOJphtUJnQ3039Nyanw0UFaYi6HhN6sJXr9GXDebXsJiZPAAbkaf 7WUHnfdVw9RIpbpDbN62Mva3etsF+XahEA4yMUktX9XOCvtnqEmcWHeY8PoQpiZ+a3UM YpMqHdMuq0txSHnzf2o/abkU0TfNc2/GwycG4mgNDmaKK2wD4H1Fwct6jfCLR8l3AqAZ 4Xhz0grp7H/3QV72reRfYb5sQXhFFTYd0fLTVM8xT3C9289K5O0UlA2Fn+wmZzySXsyw hApg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=mHERE8Ht7Z4ovtjghyF5hK9A/Lo1ZaNeNeJNzV0B+CQ=; b=D6LcJJkOdZK8279jJgCE7NIIM3aX5gIiS0q3pZDqWr563dlIaFNfmmjI54YaTbFYrj v7WTtqihfwoR3xo3CDCLo/c8D4c/W7hs1t/QvVIssYQT4pWZbX9FUYDFbeLUlL3344Ft oOFsXlSrNkaxYZ2+1Ruhm9sJal7qShSoNOKoEuFczH/0XiA31eeSUPmhRqeqehhzdOeL B73JxXWOHf8WejllL88ABhoKplPdiGlo9R6kXCteIUrLagcKra3aAp0L30RSYQtXfIPv loxl6Yuwy9M2udsrS+jcl1EIiaweIZGLaqlHL3/TMGD8ychgaWSAbErDhS9VhcNCvxo3 4X8Q== X-Gm-Message-State: ALKqPwcc0xUW7g8rZTPqCaCoPw/2a+1Ai/AHZuEFyGaZyI4RqW3A8v7e AewXY6bxzexMOAhoREj6bckL7cRK0RY8lPxDOF2O7cbc X-Google-Smtp-Source: AB8JxZqXjKTJQPFGUWJa5hUnyndAOIxl9rjleZYecD9Sy/6W9wO/MnwaycrFVsje4dx7KuGkSDvzTahdRD6jPDhSrPc= X-Received: by 2002:aca:4f57:: with SMTP id d84-v6mr4253917oib.138.1527184836942; Thu, 24 May 2018 11:00:36 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:ac9:2350:0:0:0:0:0 with HTTP; Thu, 24 May 2018 11:00:16 -0700 (PDT) In-Reply-To: <CAN-r--nRo=eYwYz6GEzCqqsJEBJiu1PXt_ChEAAgQnE0WGu2=w@mail.gmail.com> References: <CAN-r--=mq7bm1PUpP61Y-7QFsTMWf6=5U8gooE1Z0kmbnOzQqg@mail.gmail.com> <CAN-r--kN98ZVnHvsPbZTkhy4s=6g53qRC4ASGaXpd6jO-EkBPQ@mail.gmail.com> <CAN-r--nRo=eYwYz6GEzCqqsJEBJiu1PXt_ChEAAgQnE0WGu2=w@mail.gmail.com> From: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Date: Thu, 24 May 2018 20:00:16 +0200 Message-ID: <CAFBinCDzCU520=1qOVPBzf_o3BoceQQj6R5Ls32_YVJB3+12EQ@mail.gmail.com> Subject: Re: [OpenWrt-Devel] 18.06 Bug: Baby Jumbo Frames on mt7621 To: Jaap Buurman <jaapbuurman@gmail.com> Cc: openwrt-devel@lists.openwrt.org, Mathias Kresin <dev@kresin.me> Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180524_110049_030371_19B207CD X-CRM114-Status: GOOD ( 16.27 ) X-Spam-Score: -0.1 (/) X-Spam-Report: SpamAssassin version 3.4.1 on bombadil.infradead.org summary: Content analysis details: (-0.1 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [2607:f8b0:4003:c06:0:0:0:244 listed in] [list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (martin.blumenstingl[at]googlemail.com) -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid Hello Jaap, On Thu, May 24, 2018 at 12:00 PM, Jaap Buurman <jaapbuurman@gmail.com> wrote: > Dear all, > > I found some additional information in the system log: Thu May 24 > 11:38:39 2018 kern.err kernel: [83864.729458] eth0: Invalid MTU 1508 > requested, hw max 1500 > Digging deeper, this seems like a message that is spawned by a > function in /net/core.dev.c of the linux kernel: > > if (dev->max_mtu > 0 && new_mtu > dev->max_mtu) { > net_err_ratelimited("%s: Invalid MTU %d requested, hw max %d\n", > dev->name, new_mtu, dev->max_mtu); > return -EINVAL; > } > > Is there anybody that happens to know where exactly this max_mtu value > is set to 1500? For mt7621 devices this should be 2048 (Baby jambo > frames). > > Thank you very much in advance. > > Yours sincerely, > > Jaap Buurman > > On Tue, May 22, 2018 at 3:05 PM, Jaap Buurman <jaapbuurman@gmail.com> wrote: >> Dear all, >> >> The switch to the 4.14 kernel apparently broke the baby jumbo frames >> support of 2048 bytes that the switch is capable off. I found out that >> changing the mtu above 1500 via Luci no longer applies properly. >> Trying to manually change the mtu via ssh also fails: >> >> root@LEDE:~# ifconfig eth0 mtu 1508 up >> ifconfig: SIOCSIFMTU: Invalid argument >> >> If there is any additional information that I can supply, please let >> me know. I am also more than willing to help test potential fixes :) I *believe* Mathias has a fix for this in his tree (but I'm not sure if he has the hardware to test it): [0] maybe you can give it a go and report back? Regards Martin [0] https://git.openwrt.org/?p=openwrt/staging/mkresin.git;a=commitdiff;h=cc5f1fe7aa02943f3b39ffbd9dc3b8fcad569c8f ]